EFFECT OF TRANSVERSE REINFORCEMENT FOR MISSILE IMPACT ON REINFORCED CONCRETE SLABS

摘要

This paper describes work conducted by the Canadian Nuclear Safety Commission (CNSC) on analysis of reinforced concrete slabs under missile impact. Non-linear dynamic behavior of reinforced concrete slabs under impact loading by "hard" missile was analyzed using commercial Finite Element (FE) code LS-DYNA. FE predictions based on Winfrith concrete material model were compared for slabs with and without transverse reinforcement. Identical material properties and geometry for both missile and slab were used, so the only variable was transverse reinforcement. No pre-stress was applied to target in this study. Concrete reinforcement was modeled using beam FE coupled with 3-D concrete FE at coincident nodes. Two different types of transverse reinforcement were examined (stirrups and T-headed bars) using simplified models. Wide range of impact missile velocities (60 - 120 m/s) resulting in response from missile rebound to target perforation was simulated. FE predictions show that transverse reinforcement localizes damage induced by missile. However, this reinforcement does not increase the perforation resistance of the concrete target. Moreover, transverse reinforcement using stirrups could lead even to reduced perforation resistance. FE predictions also show that T-headed bars perform better than stirrups providing approximately the same perforation resistance and smaller damaged area comparing with target with longitudinal reinforcement only. FE predictions obtained are "blind" results. However, they are in general agreement with tests designed by CNSC and performed one year later at VTT Technical Research Centre (Finland). These tests are presented in a separate SMiRT-22 paper (Orbovic and Blahoianu (2013)).