Strengthening Behavior of Steel Beams Under Varied Eccentricity Locations and Jacking Stress

Abstract

Thirteen simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of these beams have the same steel section, clear span length and strengthening by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands are divided into two groups according to jacking stress. Each group consists of six steel beams divided according to the eccentricity location of prestressing strand ranging from (0 to 165) mm at jacking stress1120.061 MPa and 814.589 MPa respectively. During the teste, it was found that the load deflection curves behavior for the beams strengthening by external prestressing strand are stiffer than the reference beams and the percentage of stiffening is slightly increase with increasing the jacking stress at constant eccentricity. Also, the maximum applied load with increase slightly rising as eccentricity increased at mid span. On the other hand the increasing percentage in maximum deflection decreases when the jacking stress increase from (814.589 to 1120.061) MPa at constant eccentricity locations.