6/19/13

1

Seismic Design of Reinforced Concrete Mat Foundations: NEHRP Seismic Design Technical Brief No. 7 An Overview

Ron Klemencic, P.E., S.E. FACI

6/19/13

2

Soil pressure under centrally loaded foundation

6/19/13

3

Bearing pressure distribution example (peak value shown in grey color)

USD v. ASD

6/19/13

4

Seismic Demand Levels n Direct Assessment using NLRHA n Over-strength Factors n Reduced, R

= 0.6

6/19/13

5

Examples of critical punching perimeter at shear walls

6/19/13

6

6/19/13

7

6/19/13

8

Backstay effect on moment diagram

6/19/13

9

WIDTH?

6/19/13

10

Example of edge reinforcement at mat foundation edge

Example of placement diagram to clarify layering

6/19/13

11