Part2 W01 MasterKey Wind Loading to BS 6399 by wanghonghx

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									20 MasterKey Wind Loading to BS 6399 Pt2


20.1 Introduction

You can use MasterKey Wind Analysis to quickly and accurately determine
wind pressures for any site in Great Britain, using the built-in O.S. location map
or by entering a grid reference. You have a choice of several wind analysis
methods with which to refine the wind pressures for your particular site. For the
use of the MasterKey Wind Analysis program as a stand-alone module refer
exclusively to section 2 in this manual.

MasterKey Wind Analysis on its own gives you only a fraction of the power of the
complete system. For you to reap the full benefits, MasterKey Wind Analysis
integrates with the 3D Model Manager to give you the most powerful tools
available for automatically applying wind loads to any structure. For the use of
MasterKey Wind Analysis with the 3D Model Manager refer to section 3 in this
manual.

The good news for users throughout Ireland and countries elsewhere in the world
is that you too can unleash the potential of the integrated system. All you need to
do is enter the relevant site information and basic wind speed in the MasterKey
Wind Analysis to evaluate the wind pressures and then use the integrated
system to apply the wind loadings to your building.



20.1.1 MasterKey Wind Analysis

First we will look at the MasterKey Wind Analysis interface and understand how
to use it, before examining how it integrates with the 3D Model Manager and
MasterFrame.

Select the „MasterKey Wind Loading to BS 6399‟ from the Designer Suite menu.



20.1.2 Choosing a Site Location from the Wind Data Map

A location is chosen from the MasterKey Wind Analysis site data map or if
outside Great Britain, a default site can be set up to generate the wind pressures
for a particular location. Pick a site directly off the map or enter the site grid
references, if known, to get exact site information. (Note - grid references can be
obtained from various internet sites, for example, www. multimap.com, based on
the site address or post code.)

                          MasterKey Wind Loading to BS 6399                    20-1
Accurate wind and topographical information is contained within the Wind Map
database. This information is used by the program to obtain the wind pressures
on a structure as it varies with height and orientation. Several wind diagonal
lengths can be taken into account. The user can choose which analysis method
to employ.




           Typical Wind Loading screen (linked to 3D Model Manager)


The Town/Country, Topographical and Categories maps are displayed at the top
right of the screen. Below these, the town/country/sea distances for the local
area and the wind pressure distribution for the site, varying with height, are
displayed. All the site data and wind pressures are shown in the calculations area
on the left of the screen.




                          MasterKey Wind Loading to BS 6399                   20-2
20.1.3 Site Data interface

The Site Data tab enables you to enter a title for each brief, add and sort briefs
and select which map type to be the main graphic. The grid references are
shown here and can be manually changed if you know the exact grid references
for your particular site. The basic wind speed and site altitude are given. The
data for a particular site can be saved as an independent file for future re-loading
(Save/Load Site for BREVe2). If the site is outside Great Britain, you can set up a
file containing a default (overseas) site, using the Set Default Site button. The
site information for an overseas site is entered in the following tabs, so that the
wind pressures can be accurately calculated.




                             When used with the 3D Model Manager, the Site
                             Data tab also allows you to specify the orientation of
                             your building relative to the North, so as to ensure
                             accurate application of the wind loading to the
                             individual faces of the structure.




20.1.4 Obstructions interface

If there are obstructions in the vicinity of the structure being examined, these can
be taken into account by specifying the height of and distance to the obstructions
at intervals of 30 degrees around the building.

If the orientation of the building is known, the UK Sd factors can be used to
reduce the wind pressures around the building. If the orientation is not known or
is outside the UK, the Sd factors should be set equal to 1.




                           MasterKey Wind Loading to BS 6399                    20-3
20.1.5 Sea/Country/Town interface

Fetch distances and category types are automatically included when a site is
selected from the Great Britain map. For a site outside Great Britain, the values
can be entered manually for each orientation.




20.1.6 Topography interface

The local topography can be taken into account resulting in modification of the
wind loading. This can be done using the internal data within the wind map or
altered manually.




                          MasterKey Wind Loading to BS 6399                    20-4
Alternatively, a previously saved file (*.Shf) can be used to bring the local
topography data into account, or…




… the user can set their own data for a site.




There is also an option to use the site altitude only to evaluate the wind loading
ignoring the effects of local topography.




                           MasterKey Wind Loading to BS 6399                    20-5
20.1.7 Report (Output) interface

On the Report (output) tab, the user can select which method to employ for the
calculation of the wind loads – Standard, Hybrid, Directional or Designer‟s Guide.
Having settled on the appropriate method, the screen and printing output options
can be selected. The basic wind speed automatically selected from the map may
be changed if desired, as can the start and length of the season under
consideration. Building floor levels and wind diagonal lengths can be changed
from the defaults if necessary (note – when used in conjunction with the 3D
Model Manager, these values are automatically taken from the model). Select the
risk period from the droplist. Finally the graphics scale and number of segments
can be varied. The wind pressure diagram can be viewed for each wind diagonal
length a.




20.1.8 Printing Results
MasterKey Wind Analysis results can be printed to a printer or PDF file or
exported to Word (PowerPad users) using the Print and PowerPad facilities in
the top menu or the buttons described below:-

            Ensure graphics are always on top.
            Switch graphics on or off when exporting or printing.
            Edit project title and job references.
            Print current or all briefs to printer.
            Export current or all briefs to Word (PowerPad users only).




                           MasterKey Wind Loading to BS 6399                  20-6
20.1.9 Viewing of Local Category Map and Wind Pressures Diagram
The local category map and wind pressure diagram can be manipulated using
the following buttons from the top menu:-

            3D view                             Place on plan
            Front view                          Shade wind pressure diagram
            Side view                           Rotate diagrams
            Plan view (north)                   Alter vertical scale of wind
                                                pressure diagram
            Elevation



20.1.10 File Management
Files and briefs can be managed using the options from the File and Editing
menus or using the following buttons from the top menu:-

            Open a new file                         Copy current brief to
                                                    clipboard
            Open an existing file
                                                    Add new brief from clipboard
            Save current file
                                                    Add new brief
            Delete current brief
                                                    Next or Previous brief



20.1.11 Additional Help on the BreVe2 Wind Loading

Help can also be found in the BreVe2 Help system, which will have been loaded
when the Wind Loading module was added to your MasterSeries programs. To
access the BreVe2 help, go to Start>Programs>BreVe2>BreVe2 Help and
search for the required information.




                         MasterKey Wind Loading to BS 6399                     20-7
20.2 MasterKey Wind Loading + 3D Model Manager


MasterKey Wind Analysis integrates with the 3D Model Manager to give you
the most powerful tools available for automatically applying accurate wind loads
to any structure, saving you time and effort.
The MasterKey Wind Analysis automatically calculates and applies the weighted
external pressure coefficient “Cpe” to be used with each wind loaded member for
each wind direction.
The value of Cpe is dependent on the wind surface angle to the horizontal , the
angle between the wind direction and the normal to the wind surface  and the
wind zone depending on the position of the member within the wind surface and
the building as a whole, the wind zones are:
      A-D and H-K for walls and inclined walls
      A-G and X-Y for flat roofs, and
      A-J and K-S for monopitch and duopitch roofs.




               Wall Zones                                        Flat Roof Zones




                            Duopitch Roof Zones (including roof angle)


Adjustments are automatically made for corner angles , funnelling effects 0.25b
to 1.00b, re-entrant corners and both narrow and wide recesses (introducing
zone c1 in the wedge).

                             MasterKey Wind Loading to BS 6399                     20-8
The program will dynamically change all Cpe values for any changes you make
to wind directions at any time. All angular values including ,  and  and all
member zoning locations are dynamically determined by the program. To ensure
maximum flexibility you will however be able to overwrite some or all of these
values.

The method of application can be clearly explained by the following steps.

   Step 1 - Turn on the „Use MasterKey Wind Loading‟ option.
   Step 2 - Specify the wind diagonals (a values) for different members in the
            structure.
   Step 3 - Specify internal pressure coefficients and internal suction coefficients
            for each wind direction if necessary, e.g. in cases of dominant
            openings
   Step 4 - Specify the Wind Directions you wish to consider on the structure
   Step 5 - Create the Wind Loading cases using the automatic generation tools
   Step 6 - Enter the MasterKey Wind Analysis program to determine the wind
            pressure values for the specified wind directions, wind diagonals and
            heights of the structure.
   Step 7 - Define the Wind Panels in the structure using the 3D Model Manager
            Wind Area Loading tools. In this step the coefficients of external
            pressure for each wind direction are automatically determined for
            each wind panel.




                          MasterKey Wind Loading to BS 6399                     20-9
Activating the Integration of 3D Model Manager and MasterKey Wind
Loading

To activate the integration between MasterKey Wind Loading and the 3D Model
Manager,
   1. Select 3D-Model> Area Loading Defaults
   2. Click on the „Use MasterKey Wind Loading‟             button.
   3. Click on the „X‟ at the top right of the „Titles and Load Combinations‟ to
      close this area.


20.2.1 Wind Diagonals
Begin by selecting the Wind Loading option from either the Multi-Storey or 3D-
Model menus.

BS 6399 Pt 2 (cl. 2.1.3.4) makes use of a size effect factor Ca for the
determination of the wind pressure values. This has the effect of designing of
members which are locally loaded by wind (such as cladding members) for a
larger wind pressure than members which are globally loaded by wind, e.g.
vertical bracing members. Set up the wind diagonals for the individual members
(defaults to 5m) and for the bracing systems e.g., 30m representing the wind
loading coming onto the various bracing systems.

                             Select the wind diagonals button   to move to the
                             area of the program where the diagonals and their
                             relating members can be defined.




                              All members will default to the 5m wind diagonal
                              length unless placed into a new wind diagonal
                              definition. For example, create a new definition
                              using the     button, giving it a relevant title. Insert
                              the Current Wind Diagonal length and then select
                              the members which have this wind diagonal length.

                              Tip – use the member viewing options in the top
                              right to select, say, the inclined (I) members only.
                              You can then box around these members to add
                              them to this diagonal group. Switch back to All (A)
                              members to see the full frame.




                          MasterKey Wind Loading to BS 6399                        20-10
Note – The definition of wind diagonals will result in a more efficient design,
however because the program defaults to a conservative value of 5m, specific
diagonal definitions are not absolutely necessary. If you do wish to specify wind
diagonal values, then it is recommended to keep the number of additional
diagonals to a minimum since each diagonal value will have its own set of wind
loading cases. Hence if many wind diagonals are defined, the number of loading
cases would become very large, resulting in a much increased analysis time. For
many circumstances it would be adequate to have only two diagonal values, i.e.
the 5m default diagonal and one larger diagonal value to cover all members that
will attract force due to wind load but are not locally wind loaded. The additional
larger value should be the lowest diagonal of these types of members.




20.2.2 Setting up Wind Loading Directions
Select the     button at the top right of the screen to access the area where the
wind directions are specified.

Up to 8 wind directions on the frame can be considered using the load groups
W1 to W8. The direction of the wind is defined based on the angle with the
frame‟s global X axis. In the example below W1 to W4 is used define four
principle wind directions. The angle between the frame Z axis and magnetic
North is specified in the „Angle to North‟ text box. If the „Draw Global Axis‟ icon is
turned on from the top tool bar, then the global axis symbol at the bottom left of

                           MasterKey Wind Loading to BS 6399                      20-11
the screen graphically indicates the North direction in relation to the frame global
axis.




20.2.3 Defining Internal Pressure/Suction Coefficients
These are typically required in case where there are dominant openings in a
structure. The internal pressure/suction coefficients are defined in the same
table as the wind directions. An example of how these should be specified is
shown below.


          W7 – 270 degree wind
          direction




                                                     W3 – 90 degree wind direction




For wind direction W3 it is clear that an internal pressure value is required, while
for wind direction W7 an internal suction value is needed.


                           MasterKey Wind Loading to BS 6399                         20-12
20.2.4 Setting up load cases including internal pressure and suction
All the relevant load case combinations which include wind loading can be
automatically generated with the click of a few buttons. These facilities are found
in the wind directions are and can be accessed by clicking on the      button at
the top right of the screen in the Wind Area Loading part of the program.




All ultimate and service load cases are developed in combination with the dead
and live loads, and taking into account any pressure or suction coefficients added
to the wind data.

To generate all wind loading cases,

   1. Click on the „D+W‟ button to set up the ultimate dead plus wind case for
      W1
   2. Click on the „D+L+W‟ button to add the ultimate dead plus live plus wind
      case for W1
   3. Click on the „Serviceability‟ button to add service cases for each of the
      ultimate cases already specified.
   4. The fourth button will indicate the number of wind loading cases that are
      going to be generated. Click on this button to finally generate all the cases
      for all specified wind directions, for each wind diagonal and for any internal
      pressure/suction values entered.

If the building has a basement, the depth of the basement can be entered. This
depth will be considered when the wind loads are evaluated based on the height



                          MasterKey Wind Loading to BS 6399                    20-13
of the MasterFrame model. An Augmentation factor can be entered and the UK
Sd factors switched on or off.

All loading cases generated can be edited using the normal MasterFrame load
cases facilities.

Some of the load cases developed are shown in the list below.




20.2.5 Dynamic Augmentation Factor
The value of the dynamic augmentation factor Cr is entered on the Wind Loading
tab in the Titles and Load Combinations                        .

The Dynamic Augmentation Factor 0.85(1+Cr) is applied to wind load cases
designated as W in the loadcase combinations. These W loadcases represent
the wind loading based only on the Cpe values and do not take account of
internal pressure or suction coefficients Cpi and Csi.

The internal pressure and suction load combinations are designated as P and S
loadcases and are a combination of the Cpe and Cpi coefficients for internal
pressure and Cpe and Csi coefficients for internal suction. W, P and S loadcases
are generated for the default wind diagonal length (typically 5m). These cases
should govern design of the individual elements of the structure.

For the stability of the whole structure (bracing design), the user will have already
set wind diagonal groups with diagonal values which account for the various
bracing systems in the structure. These wind diagonal values will be greater than
the default value (typically 30m or 50m). The program will generate a set of W
load combinations for the longer wind diagonal values in addition to the cases for
W,P and S mentioned above for the default length. Internal suction and pressure
are ignored when looking at the overall stability and design of the bracing
system. Therefore these additional W loadcases will be used for the bracing
design. No P or S loadcases will be generated for diagonal lengths other than the
default value.

                           MasterKey Wind Loading to BS 6399                    20-14
20.2.6 Entering the MasterKey Wind Analysis program
To move to the MasterKey Wind Analysis site data map click on the  button at
the top right of the 3D Model Manager Wind Loading. The dynamic wind
pressure values are determined by this program as follows.

   1. For buildings located in Great Britain select a site from the map as
      described in section 2.1.
   2. For building outside of Great Britain click on the „Set Default Site‟ button in
      the Site Data tab, then enter the relevant site data as described in
      sections 2.3, 2.4 and 2.5.
   3. Select a wind analysis method from the Report (Output) tab as described
      in section 2.6.
   4. You can examine the wind pressure values calculated by scrolling to the
      bottom the output screen. You will see that wind pressure values are
      determined for the different heights in the structure, for each wind direction
      specified and also for each wind diagonal.
   5. Select File> Exit MasterKey Wind Analysis, to take you back into the 3D
      Model Manager wind panels screen.

Any of the MasterKey Wind Analysis data can be changed at any time by re-
entering the program using the        icon or by selecting 3D-Model> MasterKey
Wind Analysis – Site Data.




                          MasterKey Wind Loading to BS 6399                     20-15
20.2.7 Setting up Wind Panels
To access the area used to set up the wind panels select 3D-Model> Wind
Loading.
The Wind Loading facilities in the 3D Model Manager enable the application of an
area load in the direction normal to any planar surface. The wind loading is
controlled by wind loading member groups. Each wind loading member group
defines a planar surface and contains the following information.

   1. All the wind panel members in the planar surface.
   2. The side of the surface on which the positive wind loading is applied.
   3. The load distribution characteristics on the surface, i.e. one way or two
      way spanning.


20.2.8 Working with and Managing Wind Loaded Surfaces

The Wind Load surfaces (groups) are
managed using the following icons.



                                  Drop list to move between the different wind
                                  loaded surfaces that have been defined.
          Spin button to move up and down through the list of member groups.
          Apply To mode. When this button is pressed down the Apply To
          mode is turned ON. While you are in Apply To mode any member
          you click on in the structure geometry area will be added to the
          current wind surface. You can also add a range of members to a
          group by clicking and dragging a cross window around them.
          Members can be removed from a group by clicking on the member
          again.
          Search mode. When this button is pressed down the Search mode is
          turned ON. When you click on a member while in search mode the
          wind surface to which the member belongs (if any) will become the
          current one.
          Add a new wind surface. The new group will be blank of all members
          and information until specified by the user.
          Clear all members from the current member group. The group itself
          and the information it holds will remain.
          Clear all members from all member groups of this type
          Delete the current wind surface.
          Delete all wind surfaces
          Exit the 3D Model Manager Wind Loading


                          MasterKey Wind Loading to BS 6399                       20-16
20.2.9 The Wind Loading Group Information
                                 Vertically spanning load distribution in relation to the
                                 surface template
                                 Horizontally spanning load distribution in relation to
                                 the surface template
                                 Two-Way spanning load distribution in relation to
                                 the surface template
                                 Wind loaded surface template. The span type
                                 options above apply to the orientation of the
                                 template and not the global orientation of the
                                 surface on the building. The template is defined by
                                 the members in the wind load group.
                                 Swap the Template window with the main view
                                 window
                                 Flip template about horizontal axis
                                 Flip Template about vertical axis
                                 Rotate Template 90 clockwise
                                 The Cpe values and Zones are calculated internally
                                 within the Wind Analysis program. Therefore no
                                 values are shown in this data area. The data area
                                 should only be used if the user wishes to change
                                 these calculated values or add funnelling effects.
                                 The sign of the Cpe value may be +ve or –ve. The
                                 +ve direction is indicated by red vector lines normal
                                 to the surface in the main window as shown below.
                                 Also the side of the surface being viewed in the
                                 template window represents the side on which +ve
                                 direction wind loading is applied.
                                 Occasionally some roof panels may need closing.
                                 This will be the case if the panel does not have a
                                 closing member on it‟s 4th side.
                                 Occasionally the default orientation of the surface
                                 template may need to be rotated by an amount
                                 other than 90.
                                     All members that define the panels in the current
                                     wind loaded surface. While Apply to mode is ON
                                     you can add members to this group by clicking on
                                     them individually or cross windowing for multiple
                                     member selection.




                          MasterKey Wind Loading to BS 6399                  20-17
20.2.10 The Automatic Generation of Wind Panels, Zones and Cpe Values


The wind panels for a complete building of any shape can be quickly generated
using the „Fast Selection‟ buttons. As the panels are being generated, the wind
zones and Cpe values are automatically evaluated for each surface for every
wind direction specified. The program will give each surface a relevant title based
on it‟s orientation and position within the structure, eg:- „@West Recess Bay Part
A‟. The program uses this title to assist in evaluating the zones in the panel.




                               Wind zoned building


                          MasterKey Wind Loading to BS 6399                    20-18
20.2.11 Creating the Vertical Panels
To achieve accurate wind zone results, the vertical panels should be generated
for each change in horizontal profile of the structure as shown by the coloured
zones below.
                                                                     Note the side
                                                                     panels
                                                                     around the
                                                                     small upper
                                                                     floor are in
                                                                     different
                                                                     groups than
                                                                     the
                                                                     correspondin
                                                                     g side panels
                                                                     in the lower
                                                                     part of the
                                                                     structure.




Each panel
generated must
have the wind
as external
pressure
(shown by red
arrows pointing
into the
structure) for
the program to
evaluate the
zones and Cpe
values
consistently for
each wind
direction over
the whole
structure.


To quickly generate the wind panels, zones and Cpe values for vertical surfaces
click on the       button at the bottom of the screen in the Multi-Storey > Wind


                           MasterKey Wind Loading to BS 6399                   20-19
Loading side menu. Select the direction of span of the panels – horizontal,

vertical or 2 way spanning                .



                                                                   Place the
                                                                   structure in
                                                                   side view and
                                                                   zoom dynamic
                                                                   window
                                                                   around the
                                                                   lowest uniform
                                                                   part, hence
                                                                   filtering to this
                                                                   lower inset
                                                                   storey.




Now place the part structure
in plan view. With the fast
selection button on,        click
one end of a panel and then
the other end. Alternatively,
you can box around the full
panel to select it. The panel
will appear in the top right of
the screen. Ensure that the
panel is orientated correctly
by examining the red direction
arrows. These should always
point into the structure
indicating an external
pressure. If the panel needs
reoriented, click again on
one of the members of the panel and the panel with switch round. Note that there
is no need to fill in the Cpe or Zones values in the side data panel as these will
be automatically evaluated within the program.



                          MasterKey Wind Loading to BS 6399                    20-20
Continue to select the rest of the vertical panels on this level of the structure by
clicking on their start and end members, remembering to reorient each panel if
required so that all wind directions are indicating external pressure (pointing into
the structure).




Once all the panels for this level are picked, go back to the full structure and
select the next level by placing the structure in side view and zoom dynamic
windowing round it to filter to the upper inset storey.


                                            Again, place the selected part structure
                                            in plan view and with the      button
                                            depressed, select each vertical panel in
                                            turn, again ensuring the wind direction
                                            is correct.


Carry out this procedure for all levels of the structure until all vertical panels have
been defined. Switch off the fast selection button for vertical panels.


20.2.12 Creating the Horizontal Panels
Panels should be defined at each change in level starting with the uppermost
panel and working downwards. As each lower level is defined the upper panel
areas already defined will automatically be omitted from the lower level, so that
only external areas will be included in the group.

                            MasterKey Wind Loading to BS 6399                      20-21
                                                               Switch on the „fast
                                                               selection of wind
                                                               panels‟ button      .
                                                               Placing the structure
                                                               in side view, window
                                                               around the uppermost
                                                               horizontal external
                                                               panel (roof).




Place this on plan. Select one member in the corner of the panel and one in the
opposite corner. This will highlight the whole panel. (Occasionally you may need
to add omitted members if the complete panel is not automatically selected
correctly.)

It is essential that the
panel in the window
on the right has the
same orientation and
colour arrangement as
the main panel.
Clicking on any
member of the panel
will reorient the panel.
This may need to be
carried out a couple of
times to get the panels
identically orientated.




Examining the whole structure, window the next roof level down, place it in plan
and pick the opposite corners to highlight the wind panel at this level. Note how
the program automatically omits the area covered by the upper roof previously
defined.

                           MasterKey Wind Loading to BS 6399                         20-22
The wind zones and Cpe factors for the above structure are shown below. (See
section 3.8 on how to display zones and factors.)




                         MasterKey Wind Loading to BS 6399                20-23
20.2.13 Creating the Sloped Panels

Sloped roof panels are developed in the same way as horizontal panels by
selecting diagonally opposite corner members of a panel, again ensuring the
panel orientation is aligned with the plan view of the same panel in the main
frame. When the wind zone designation letters are displayed the letter will be
preceded by the pitch for sloped panels, eg, +19F.




                          MasterKey Wind Loading to BS 6399                      20-24
Occasionally a panel may not have members on all 4 sides, particularly on roofs,
and therefore is not a closed panel. You can close the panel by entering a „Y‟ in
the data entry area.




The sloped wind panel
at the front of this roof
does not close
automatically since
there are no horizontal
members across the
top of the sloped area
of roof.




                                                                By entering „Y‟ in the
                                                                „Close Panels‟ data
                                                                entry box, the full
                                                                area of the panel is
                                                                now considered for
                                                                wind loading.




                            MasterKey Wind Loading to BS 6399                      20-25
20.2.14 Refining and Altering the Wind Information

                                           The Wind Analysis program
                                           automatically calculates all the Cpe
                                           factors, Zones and beta angles for all
                                           panels in the whole structure. These
                                           may be modified by the user if
                                           necessary using the table opposite,
                                           otherwise the table remains empty. The
                                           user can also enter the funnelling factor
                                           which is a ratio of the distance between
                                           the structure being considered and the
                                           adjacent structure, to „b‟ - the scaling
                                           length. The factor only has an effect
                                           between the ratios
of 0.25 and 1.0. A different factor may need to be entered for each wind direction.

The panel zoning can be refined by introducing additional nodes into the
members around a panel and redefining the wind panel. This will break the panel
into smaller areas resulting in redefinition of the zones and a more refined wind
loading.




        Less refined roof zones                    More refined roof zones




                          MasterKey Wind Loading to BS 6399                    20-26
                                                                 Structures such
                                                                 as that shown
                                                                 can have the
                                                                 wind loading
                                                                 accurately
                                                                 applied in a
                                                                 short space of
                                                                 time using the
                                                                 Wind Analysis
                                                                 program.




20.2.15 The Basic Rules of Wind Loading
1. Each wind load group applies a uniform wind load intensity normal to a
   planar surface
2. A wind load group can only apply to one planar surface
3. All the members that define the panels in a planar surface should be added
   to the wind load member group. This is different from the gravity area
   loading application method where only the loaded members are added to the
   group. The wind loading calculations determine which members of the
   panels are loaded and which are not according to the direction of span.
4. Unlike the gravity area loading method, bracing members do not need to be
   defined in a special bracing group, rather they are simply not added to the
   wind loading group and therefore do not affect the distribution of wind area
   loading.
5. A member can belong to more than one wind load group.
6. A panel must have three or four straight sides. A straight side of a panel can
   be made up of any number of individual elements.




                          MasterKey Wind Loading to BS 6399                  20-27
20.2.16 Wind Loading Display Tools
There are several ways in which wind loading can be displayed. While you are
viewing a wind loading group the controls at the bottom of the screen allow you
to,
       ON - View the wind load in multi-colour shading. The wind loads being
       distributed to a single member are shown in the same colour. OFF – The
       wind load distribution lines are shown in grey with no coloured shading.
       ON – Show all the wind load groups simultaneously. OFF – Only show
       the wind load distribution diagram of the current group
       ON – View the wind loading with a single colour for each group. The
       option must also be turned on. This is most useful when used along with
       the Show all groups option.

                                                    When these three display
                                                    options are selected the wind
                                                    loaded surfaces are displayed
                                                    and the program performs a
                                                    hidden surface removal.




There are also several display tools on the top tool bar, which can be used at any
stage inside MasterFrame.
     The 3D Model Manager load display options on the top tool bar are not
     activated until this button is set to ON (pressed down)
     Display all wind loading
     Draw the wind loading in shaded colour
     ON – View the wind loading with a single colour for each group. The
     and     option must also be turned on.
     While the above options are turned on, this button highlights the members in
     the wind loaded surfaces that the wind load is being distributed to.




                          MasterKey Wind Loading to BS 6399                   20-28
                                                             In screen resolutions
                                                             of 1024x768 and
                                                             higher, when the
                                                             „Draw Wind load per
                                                             intensity‟     button is
                                                             used, a drop list of
                                                             wind directions W1 –
                                                             W8 appears at the top
                                                             right of the tool bar.
                                                             When an individual
                                                             wind direction is
                                                             selected, the surfaces
                                                             are colour coded
                                                             according to their Cpe
                                                             values. Shades of
                                                             green are used to
                                                             represent suction
                                                             while shades of blue
                                                             are used for positive
                                                             pressure. This will
                                                             assist in the validation
                                                             of the wind
                                                             application.




With the wind
drawing options
selected, the wind
zone letter
designations can be
displayed by
selecting the
button.
You can view each
wind direction in turn
W1 to W8.




                         MasterKey Wind Loading to BS 6399                       20-29
                                                             With the wind
                                                             drawing options
                                                             selected, the Cpe
                                                             values can be
                                                             displayed by
                                                             selecting the
                                                             button.
                                                             You can view each
                                                             wind direction in turn
                                                             W1 to W8.




20.2.17 Viewing and Validating the Wind Loading
The various loads applied to the structure using the 3D Model Manager wind
loading are internally translated to standard MasterFrame loads. These loads
and their values can then be viewed just like any other MasterFrame Loads.
 By clicking on the     button on the top tool bar the frame load diagram is
displayed. The Frame Load Diagram enables you to view and print the applied
loads on the whole frame. You can select to view loads according to their
directions and density (D), load groups and loading cases.
The all groups drop list can be used to
select view the loads generated from
an individual wind direction.




                         MasterKey Wind Loading to BS 6399                     20-30
20.2.18 Conclusion

This concludes the wind load application using the 3D Model Manager and
MasterKey Wind Analysis.




                        MasterKey Wind Loading to BS 6399                 20-31

								
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