Seismic Design Example Static Procedure IBC 2003 ASCE 702 NFPA 5000

Static Seismic Force

A 12-story building located in downtown, Los Angeles, California. The building properties summarized in Fig. 2.46 are the same as those used in the 1997 UBC example, Section 2.13.19.1. Occupancy group II (Table 2.13 ASCE Table 1.1) SUG 1 (Tble 2.12 ASCE Table9.1.3) SDC D (Tables 2.17 and 2.18 ASCE Tables 9.4.2.1a and b) Site class as determined by project geotechnical engineer D Figure 2.46. Design example ASCE 7-02 (IBC-03), static force procedure. Figure 2.46. Design example ASCE 7-02...

Code Provisions For Wind Loads

Asce Basic Wind Speeds Maps

In recent years, wind loads specified in codes and standards have been refined significantly. This is because our knowledge of how wind affects buildings and structures has expanded due to new technology and advanced research that have ensued in greater accuracy in predicting wind loads. We now have an opportunity to design buildings that will satisfy anticipated loads without excessive conservatism. The resulting complexity in the determination of wind loads may be appreciated by comparing the...

Seismic Importance Factor IE

In seismic design, the importance factor I is used to increase the margin of safety against collapse. For example, I 1.50 for essential facilities, I 1.25 for hazardous facilities, and I 1.15 for special occupancy structures. Essential structures are those that must remain operative immediately following an earthquake such as emergency treatment areas and fire stations. Hazardous facilities include those housing toxic or explosive substances. Examples of special occupancy structures are those...

National Building Code of Canada NBCC 1995 Wind Load Provisions

Gust Factor

The reader may be wondering why, after an arguably extensive coverage of the ASCE 7-02 wind load provisions, the author would burden the text with yet another building code provision. The reason is simple Although extensive in its treatment of wind, the ASCE 7-02 does not provide an analytical procedure for estimating across-wind response of tall, flexible buildings. To the best of the author's knowledge, NBCC is the only code in North America that presents an analytical method for computing...

Seismic Strengthening Details

Eccentric Bracing And Lateral Bracing

A thorough understanding of existing construction and seismic retrofit objectives acceptable to owners and to the building official is an important consideration before a seismic retrofit is undertaken. The importance of considering global and elemental deformations at expected levels of seismic forces, not at code or design levels, cannot be overstressed. This is because even with the use of amplification factors, the deformations are at best an approximation, particularly when applied to...

First Interstate World Building Los Angeles Floor Plan

Cityspire Tower Ground Floor Plan

Nations Bank Plaza, Atlanta, GA (a) building elevation (b) typical framing plan (c) section. The core columns are braced on all four sides with diagonal bracing as shown schematically in Fig. 8.15c. Since the braces are arranged to clear door openings in the core, their configuration is different on all four sides. Steel girders 36 in. (0.91 m) deep are moment-connected between the composite columns to transfer part of the overturning moment to the exterior columns. Because the...

Steel Beam And Steel Column Without Concrete Encasement

Short Steel Links Behaviour

Steel zipper column resists unbalanced post-buckling forces in the braces. Figure 5.33. Composite concentrically braced frames (a) V-bracing (b) inverted V-bracing (c) X-bracing (d) diagonal bracing (e) two-story X-bracing (f) zipper column with inverted V-bracing. Composite braces of either concrete-filled steel tubes or concrete-encased steel braces may be combined with steel frame elements. Composite columns may also be used in conjunction with composite floors and steel bracing members, as...

Composite Building Systems

Shear Wall Steel Frame Construction

Composite building systems may be classified into the following categories 1. Composite shear wall system. 2. Composite shear wall-frame interacting system. 4. Composite vertically mixed system. 5. Composite mega frames with super columns. Figure 5.7. Moment transfer between steel beam and concrete wall. Figure 5.7. Moment transfer between steel beam and concrete wall. Figure 5.8. Composite shear walls with steel plates (a) plan (b) section. Figure 5.8. Composite shear walls with steel plates...

Six Component Of Wind

Strouhal Number Vortex Shedding

A wind velocity having a specific mean recurrence interval. Mean recurrence intervals of 20 and 50 years are generally used in building design, the former interval for determining the comfort of occupants in tall buildings subject to wind storms, and the latter for designing lateral resisting elements. In general, wind buffeting against a bluff body gets diverted in three mutually perpendicular directions, giving rise to forces and moments about the three directions. Although all six...

Tuned Liquid Column Damper

Tuned Liquid Column Damper Tlcd

A tuned liquid column damper (TLCD) is in many ways similar to a TMD that uses a heavy concrete block or steel as the tuned mass. The difference is that the mass is now water or some other liquid. The damper is essentially a tank in the shape of a U. It has two vertical columns connected by a horizontal passage and filled up to a certain level with water or other liquid. Within the horizontal passage, screens or a partially closed sluice gate are installed to obstruct flow of water, thus...