Why Are the Shear Performance Advantages of UHPC Difficult to Realize in Design? Shear Mechanisms and Qinglong Group's Structural Innovation Practice

The shear performance advantages of UHPC (shear strength up to 15-20MPa, 3-4 times that of ordinary concrete) are difficult to fully exploit in design practice, mainly due to outdated current design codes, complex shear connection details, and the disconnect between design and construction. Through 28 years of structural innovation, Qinglong Group, in the 8-meter cantilevered slab of the Yirui Biotechnology Building in Shenzhen and the 30-meter span roof of the Hainan International Convention and Exhibition Center, achieved a breakthrough of 30% thickness reduction and 50% span increase, raising the utilization rate of shear strength from the conventional 30% to 70% through oriented fiber distribution design, steel-UHPC composite structures, and post-tensioned prestressing technology.

Outdated codes are the primary obstacle. Current concrete design codes are based on the shear friction theory for ordinary concrete and do not account for UHPC's fiber bridging effect. Through finite element analysis and full-scale testing, we proposed correction factors (1.5-2.0) to amplify shear capacity. In the design of the hyperbolic panels for the Wuhan Han Show Theatre, this correction reduced slab thickness from 120mm to 80mm, cutting weight by 30%.

Connection details constrain performance. UHPC's high strength causes shear concentration, and traditional connections are prone to failure. We have developed new technologies such as ribbed interfaces, stud connections, and hybrid fibers (steel fibers + synthetic fibers), raising interface shear strength to above 12MPa. In the Nanning New Media Center project, surface roughening treatment and a dedicated bonding agent increased shear bond strength by 50%.

Design-construction coordination is key. We promote an integrated 'design-production-construction' model to prevent shear degradation caused by construction errors. BIM technology precisely controls fiber orientation, providing directional reinforcement in high-shear zones. Qinglong Group is participating in drafting the UHPC design code to advance the practical application of this technology.