INTRODUCTION TO STRUCTURAL DESIGN LOAD FOUNDATION ENGINEERING Consolidation

# Introduction to structural design load foundation

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INTRODUCTION TO STRUCTURAL DESIGN LOAD FOUNDATION ENGINEERING Consolidation 6/12/2019 37 University of the Immaculate Conception Engineering and Architecture Program Exposure B: For buildings with a mean roof height of less than or equal to 30 ft (9.1 m), Exposure B shall apply where the ground surface roughness, as defined by Surface Roughness B, prevails in then upwind direction for a distance greater than 1,500 ft (457 m). For buildings with a mean roof height greater than 30 ft (9.1 m), Exposure B shall apply where Surface Roughness B prevails in the upwind direction for a distance greater than 2,600 ft (792 m) or 20 times the height of the building, whichever is greater. Exposure C: Exposure C shall apply for all cases where Exposures B or D do not apply. Exposure D: Exposure D shall apply where the ground surface roughness, as defined by Surface Roughness D, prevails in the upwind direction for a distance greater than 5,000 ft (1,524 m) or 20 times the building height, whichever is greater. Exposure D shall also apply where the ground surface roughness immediately upwind of the site is B or C, and the site is within a distance of 600 ft (183 m) or 20 times the building height, whichever is greater, from an Exposure D condition as defined in the previous sentence.
INTRODUCTION TO STRUCTURAL DESIGN LOAD FOUNDATION ENGINEERING Consolidation 6/12/2019 38 University of the Immaculate Conception Engineering and Architecture Program The wind speed-up effect shall be included in the calculation of design wind loads by using the factor K zt : K zt = (1 + K 1 K 2 K 3 ) 2 where K 1 , K 2 , and K 3 are factors. K zt = 1.0 (homogenous topography) Wind Speed-Up over Hills, Ridges, and Escarpments
INTRODUCTION TO STRUCTURAL DESIGN LOAD 6/12/2019 39 University of the Immaculate Conception Engineering and Architecture Program
INTRODUCTION TO STRUCTURAL DESIGN LOAD 6/12/2019 40 University of the Immaculate Conception Engineering and Architecture Program
INTRODUCTION TO STRUCTURAL DESIGN LOAD FOUNDATION ENGINEERING Consolidation 6/12/2019 41 University of the Immaculate Conception Engineering and Architecture Program It provides separate wind loading criteria for two analytical procedures: the “Directional Procedure” : it provides specification of pressure and force coefficients associated with specific directions (e.g., windward wall, leeward wall, and others). It applies to the determination of MWFRS wind loads on enclosed, partially enclosed, and open buildings of all heights the “Envelope Procedure” : it provides pressure coefficients that are independent of wind direction. It applies to the determination of MWFRS wind loads on low-rise buildings (A low- rise building is defined as a building with mean roof height h less than or equal to 60 ft, and the height h does not exceed the least horizontal dimension.)
INTRODUCTION TO STRUCTURAL DESIGN LOAD FOUNDATION ENGINEERING Consolidation 6/12/2019 42 University of the Immaculate Conception Engineering and Architecture Program It provides separate wind loading criteria for two analytical procedures: the “Directional Procedure” :

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