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Wind Effects on Buildings: Database Assisted Design |
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| Introduction |
Increased computational power and advances in pressure measurement
capabilities led to the development of the database-assisted design
(DAD) concept. DAD makes direct use of pressure time histories
measured at a large number of pressure taps placed on the facades
of wind tunnel building models. Site-specific directional extreme
wind speeds are used in conjunction with the measured pressure
coefficient time histories to obtain estimates of peak wind effects
with specified return periods for use in structural design. Wind
effects of interest may include internal forces and bending moments,
demand-to-capacity indexes, deflections and accelerations.
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| DAD_ETABS Software | The design of high-rise buildings is typically performed by structural designers by using the structural analysis and design program ETABS software. The software DAD_ETABS v. 1.0 was developed to enable the use of Database-Assisted Design (DAD) of high-rise buildings for wind in conjunction with ETABS. The marriage of DAD with ETABS significantly enhances the capabilities of both programs. DAD allows the direct use of wind-tunnel measurements of time-varying pressure coefficients to determine the wind loading induced by directional wind speeds. Structural and dynamic analyses by ETABS make it possible to determine any desired building response (i.e., member Demand-to-Capacity Indexes (DCI), inter-story drift ratios, floor accelerations) as a function of wind speed and direction. ETABS constructs representations of this function for any desired responses. These representations, called response surfaces, are properties of the structure independent of wind climate, and are used by ETABS to construct response matrices for as many responses as are required for structural design purposes. The elements of a response matrix are responses induced by their counterparts in the matrix, supplied by the wind engineering laboratory, of the extreme directional wind velocities at the building site. For any response being considered, the set whose members are the largest entry in each row of the response matrix is a data sample of the largest responses induced in the structure by those extreme directional speeds. The N-year response being considered is obtained from that sample by using any appropriate extreme value estimation tool. |
| Software Needed |
This program needs ETABS 18.1 and above. Since the application is
developed in a MATLAB based environment, it also needs a MATLAB
runtime version 9.5 (R2018b). This can be downloaded from the
following link:
https://www.mathworks.com/products/compiler/matlab-runtime.html Page 25 of the User's Manual provides further instructions on installing the MATLAB runtime. It should be noted that although the software is implemented in MATLAB the user of the software does not enter MATLAB commands and does not need to have any prior knowledge of MATLAB. The user’s manual is available at https://doi.org/10.6028/NIST.GCR.22-035 or http://nvlpubs.nist.gov/nistpubs/gcr/2022/NIST.GCR.22-035.pdf Version 1 of the DAD ETABS software for Windows platforms can be downloaded at
Section 2 of the user's manual provides the details on how to deploy this program. The current version of the software is applicable to prismatic steel structures with rectangular shape in plan. Minor additions to the software are currently being developed with a view to extend the applicability of the software to reinforced concrete buildings and buildings with any irregular shape. |
| Rigid and Flexible Buildings |
Database Assisted Design
The following sites contain Matlab software (and associated
documentation), pressure databases, and sample wind data sets
for several types of buildings.
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Date created: 11/30/2018 |
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