Ultimate Strength and Deformability of 780MPa-Grade High-Quality Steel Plates Jointed with High-Strength Bolts

新开发的低屈服比的780MPa级优质钢（以下简称780MPa钢）。为了将这种新型钢材用于与高强度螺栓连接的受拉构件，有必要了解螺栓孔布置和边缘距离对连接板的极限强度和破坏模式的影响，这决定了板的几何特性。对780MPa钢板的接合部分进行了两项试验：试验1：拉伸试验对钢板的极限强度和破坏模式进行了试验2：弯曲试验对h型梁受拉法兰的极限强度和破坏模式进行了试验1的试件采用12mm厚的钢板制作。使用的螺栓孔排列为2x2（2排2线）、2x3.2x4、3x3和4x3。“试验2”的梁试件由H-200x125x9x12截面制成。所采用的张力法兰螺栓孔布置分别为2x2和2x3。结果表明，钢连接板的破坏模式为网截面断裂、撕裂断裂和端部断裂。梁翼缘主要为撕裂断裂和端部断裂。以下是concidered:(1)预测极限抗拉强度的板和法兰为每个距离,(3)板的失效模式和几何属性,(4)法兰的强度极限和几何属性,和(5)板的变形能力和beamsThe有用的和实际的设计数据的高强度螺栓接合紧张的法兰板和梁,780 mpa钢铁做的,。

780MPa-grade high-quality steel (hereafter 780MPa steel), which has a low yield ratio, has been developed newly. In order to use this new steel for tension members jointed with high-strength bolts, it is essential to understand the effects of bolt-hole arrangements and edge distances, which determine the geometric properties of plates, on the ultimate strength and the failure mode of the joint plates. The following two experiments were conducted on the joint part of the 780MPa steel plates :Test 1 : Ultimate strength and failure mode of steel plates by tension testsTest 2 : Ultimate strength and failure mode of tension flanges of H-shaped beams by bending testsTest specimens of "Test 1" were made of plates of 12mm thick. The bolt-hole arrangements used were 2x2 (2 rows and 2 lines), 2x3.2x4,3x3 and 4x3. The beam specimens of "Test 2" were fabricated from a H-200x125x9x12 section. The bolt-hole arrangement of the tension flanges used were 2x2 and 2x3.It was confirmed that the failure modes for the steel joint plates were net section fracture, tearing fracture and end fracture. While those for the flanges of the beams were tearing fracture and end fracture. The followings are concidered : (1) the prediction of the ultimate tensile strength of the plates and the flanges for each distance, (3) the failure mode and the geometric properties of the plates, (4) the ultimate strength and the geometric properties of the flanges, and (5) the deformation capacities of the plates and the beamsThe useful and practical design data on the high-strength bolted joints of the tension plate and the flange of the beams, which were made of 780MPa steel, were obtained.