High performance concrete beams subjected to shock waves from air blast, psrt 2

Authors:

  • Magnusson Johan
  • Hallgren Mikael

Publish date: 2003-01-01

Report number: FOI-R--1116--SE

Pages: 67

Written in: English

Abstract

This investigation involves testing of reinforced concrete beams of high strength concrete (HSC). A total of 16 beams were tested, of which 12 were subjected to air blast loading. Concrete with nominal compressive cube strengths 140 and 200 MPa were used and most beams also contained steel fibres. Also, beams with two concrete layers of different strength were tested, i.e. the bottom layer of concrete grade 40 and the top layer of grades 140 or 200. The purpose of this investigation was to study the structural behaviour of the concrete beams subjected to air blast loading. The tests are complementary to previous test series including also beams of normal strength concrete (NSC). In the static tests, the beams were loaded with four point loads and the air blast tests were performed in a shock tube. The mass of the explosive charge was varied for the different beams and ranged from 2.0 kg up to 5.5 kg and was positioned 10 m from the beam. After the air blast tests additional static tests were performed to quantify the residual strength of the dynamically tested beams. The beams that fractured failed in flexure. It was observed that the inclusion of steel fibres in the matrix increased the ductility of the beams. Calculations of the static bending moment capacity according to the Swedish design code were made, which resulted in conservative predictions of the test results. This investigation also indicates that beams subjected to air blast loading obtained an increased load capacity when compared to the corresponding beams subjected to static loading.