Design and Construction of Steel Plate Shear Walls - Eatherton ...

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(a)(b)(d)Figure 4 – Comparison buildings designedwith special plate shear walls (a), specialconcentrically braced frames (b) and specialmoment frames (c). Elevation view of theSPSW design (d).(c)Table 1.Factors for comparing SPSW, SCBF and SMF lateral resisting systems.Cost / Construction Design Architectural PerformanceSteel % of # of Number Resp. Cntllng Column Length Roof RepairWeight SMF Field of Field Mod. D/C Width Wall Defl. afterSystem (kips) Wt Pieces Welds R Ratio in Wall Used ∆m EQSPSW 173.8 87% 150 0 7.0 0.96 12" 120’ 3.1” Replace PlateSCBF 158.1 79% 162256fillet 6.4 0.97 6" 480’ 0.25” Replace BracesSMF 200.2100% 182 96 CJP 8.5 0.88 16" 0’ 9.0” Not as Easy
The last column shown in Table 1 is meant to point out the repair options that might beavailable after an earthquake. In the braced frame and SPSW it would be possible to replacedamaged components, while repair methods for moment frames would require additional work.Successful SPSW Projects in Northern CaliforniaThe author has been involved with three large residences where SPSW was determined tobe the best option. All three are in the final phases of construction at the end of 2005. Thereasons for using SPSW are described in the following list:1. Speed of construction. One of the residences had a very short construction schedule.It was determined that fully shop fabricated SPSW would allow faster erection.2. All three of the projects are highly architectural in that there are very few lengths ofsolid walls. It was necessary to fit lateral resisting elements into short lengths ofwalls or use moment frames. SPSW allowed the used of very slender elements (seefig 2).3. Braced frames in tall slender configurations require large gusset plates.Configurations as slender as shown in Fig 2 would not be practical as a braced frame.4. Thickness of walls was also important to the architects. Moment frames that wouldrequire thick walls or bump-outs to hide large columns was not an option.5. As is shown in the preceeding section, SPSW yields less structural steel weight andshould therefore be cheaper than moment frames.All three projects were designed before the AISC Seismic Provisions were available. Thedesigns were carried out using the Canadian Steel Code (CAN/CSA 2001). 2d pushover modelswere used to verify the designs. 12 gage and 14 gage web plates were used and small angleswere attached to the columns to provide a surface to which the plate was welded. Some type offish plate or angle was needed to allow for tolerances in the plate and column. Care was takennot to attach anything to the web plates or to drill holes through the web plate for plumbing orconduit. A gap of approximately 1” was left between infill studs and the web plate in an effortto reduce damage from minor earthquakes that might buckle the plate.ConclusionsSteel plate shear walls were an excellent choice of lateral systems for three largeresidences in Northern California. The high capacity possible in a SPSW panel that is relativelytall and slender helped satisfy the restrictive architectural requirements. A cost comparisonshows that the design of a sample 2 story building required 13% less steel than a comparablemoment frame and if detailed properly would not require field welding.The 2005 AISC Seismic Provisions and the upcoming AISC Design Guide for steel plateshear walls will give SPSW a new level of exposure among practicing engineers. The followingare suggestions for further research and future editions of the SPSW design provisions:1. It should be defined whether intermediate HBE’s (between floors) require momentconnections to the VBE’s. Also it should be stated that intermediate HBE’s do notrequire lateral bracing if the VBE is designed accordingly.2. Further research should be conducted to determine what level of plate slenderness causes
Page 1 and 2: Proceedings of the 8 th U.S. Nation
Page 3 and 4: judgment outside of what is present
Page 5 and 6: for service loads, e.g. a stout win
Page 7: The special moment frame option was

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