الفهرس | Only 14 pages are availabe for public view |
Abstract Torsion can be a significant action in many structural members that are part of civil engineering infrastructure. Curved bridges, spiral stair cases, eccentrically loaded box girder bridges, cantilevered slabs and spandrel beams under gravity loads exhibit torsional forces. Most of the recent researches study the behavior of fiber reinforced polymer (FRP) strengthened reinforced concrete beams subjected to torsional loads .Many analytical and experimental methods were introduced for evaluation of the torsional capacity of FRP, but developing the common method of reinforcement (longitudinal or transverse) to improve the torsional resistance of RC structural elements had paid less attention, hence comes the importance of this thesis which offer a new technique of reinforcing RC beams so that to over come the cease of additional loads resistance. This technique based on nsmg the capacity of RC elements subjected to torsional loading which develops shear stresses by using transverse in different configuration, the shape of the stirrups was ellipsoidal and spiral. The effect of other parameters such as variation in longitudinal steel amount and fiber addition was also investigated. The main objective of this study is to give better understanding of the torsional behavior of rectangular reinforced concrete beams reinforced with different transverse steel configurations. The experimental program involves testing twenty one reinforced concrete beams with Rectangular cross section to study their torsional behavior. Three beams were kept as control beams. The rest of the twenty one beams were divided into six groups. Groups (G 1, G2 and G3), contains three beams each, of ellipsoidal, spiral stirrups configuration and different longitudinal reinforcement amount respectively. Groups (G4, G5 and G6) identical to the previous groups in -addition to this certain volume percentage of polypropylene fiber were added to concrete mixture. The most important variables studied in this research were different transverse scheme, longitudinal reinforcement amount and the addition of polypropylene fiber to the mixture. The beams dimension and surface preparation were nearly identical. All beams were tested under identical loading condition. During the tests, cracking loads, ultimate torsional loads and angle of twist were measured. |