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NEWBuildS Tall Wood Building Design Project – Structural Design and Analysis. Zhiyong Chen & Minghao Li University of New Brunswick, University of British Columbia. www.NEWBuildSCanada.ca. Location and Design Data. North Vancouver : “high earthquake, wind and rain”
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NEWBuildS Tall Wood Building Design Project – Structural Design and Analysis Zhiyong Chen & Minghao Li University of New Brunswick, University of British Columbia www.NEWBuildSCanada.ca
Location and Design Data North Vancouver: “high earthquake, wind and rain” Climatic Design Data (Per BCBC 2012) Ground Snow Load: Ss=3 KPa, Sr=0.3 KPa Plus snow built up where applicable Hourly Wind Pressure: 0.35kPa (1/10) and 0.45kPa (1/50)
Lateral load resisting system: SCL core + CLT moment frame (“Strong column-weak beam” balloon-frame) Gravity resisting system: CLT roof / floors SCL core + CLT moment frame + post-beam frame Seismic force modification factors: Rd = 2.0 and R0 = 1.5 Connection: HBV wood concrete or HSK hold downs Structural Scheme
Wind Induced Response Structural integrity (building structure check and component & cladding check) under ultimate wind loads (1/50, ULS) Serviceability under service wind loads (1/10) with serviceability criteria (inter-story drift limit = 1/500, SLS) Building motions and occupant comfort (cross-wind acceleration aw and along-wind acceleration aD)
Wind Design Parameters • Pressure Coefficient • Cp=0.8 for windward walls • Cp=0.5 for leeward walls • Internal Pressure Coefficient • Cpi=-0.45~0.3 Category 2 • Exposure B • (rough exposure, urban and suburban areas) • Ce=0.5(h/12.7)0.5 • Cg Gust effect factor • calculated by Dynamic procedure
Wind Induced Response Estimated fundamental frequency 0.25Hz < fn < 1Hz; therefore, Dynamic Procedure is required to calculate gust effect factor. P=IwqCeCgCp and Pi=IwqCeCgiCpi Calculations of Ce , Cg , Cp and Cpi follow “NBCC Structural Commentary I Wind Load and Effects”. Sufficient lateral stiffness is needed to satisfy the drift limit criteria.
Numerical Models • Beam188 elements (glulam, steel beams and columns); • Shell181 elements (floor diaphragms and shear walls); • Pinned connections; • Combin39 nonlinear springs (for hold-downs, shear connections panel-panel contacts, under development…)
Fig. I-16 Full and partial wind loads for building structure (NBCC 2010 Structural Commentary)
Building Deformations(ULS, Case A) Roof drift 89 mm (1/640) Max. Inter-story drift 4.8 mm (1/625)
Lowest Natural Frequency = 0.467 Hz for Dynamic Procedure Calculation of gust effect factor Cg Calculation of aw and aD related to building vibrations under serviceability limit state