Thinner and lighter members can be designed by utilizing the high stiffness and toughness, and high compressive strength of Ultra High Performance Concrete (UHPC), which reaches up to 180MPa. This high strength and ductile tensile behavior of UHPC makes it possible to design the web of the UHPC I Girder without conventional shear stirrups, which makes the UHPC I girder slender, light and economical. However, establishing shear design procedure for UHPC I girders without stirrups requires additional theoretical and experimental studies. This paper investigated shear behavior of UHPC I girder without shear stirrups. The test results show, in spite of no shear stirrups, test specimens have high ductility due to the bridging action of steel fibers against crack opening. UHPC I girders without shear stirrups tested show gradual increase of strength after initial cracking instead of brittle loss of strength as expected from the ordinary reinforced concrete I girders without stirrups. The decrease of the shear span-depth ratio increase the shear strength of the UHPC I girder without stirrups.

Thinner and lighter structural members can be designed by utilizing the high stiffness and toughness, and high compressive strength of UHPC(ultra high performance concrete), which reaches up to 200MPa. The punching shear capacity of UHPC was investigated in this paper aiming for the application of UHPC to bridge decks. Six square slabs were fabricated and punching shear test was performed under fixed boundary condition. Different thicknesses of test slabs, which were 40mm and 70mm, were selected. The shape ratio of loading plates were ranged between 1.0~2.5. 40mm thickness slabs showed longer softening region after the peak load and, on the other hand, 70mm thickness slabs revealed a more brittle shear failure. Experimental results were analyzed using various existing punching shear predicting equations. Ductal Ⓡ equation and JSCE equation better predicted for 40mm slabs, and Harajli et al. equation and ACI-Ductal Ⓡ equation better suited for 70mm slabs. Nevertheless generally they didn't well predict the test results. A new punching shear equation which was derived based on the actual failure mechanism was proposed. The proposed equation appeared to better predict the punching shear strength of UHPC than other available equations.

The various push-out tests have been performed to investigate the load carrying capacity and ultimate behavior of headed studs in UHPC (Ultra High Performance Concrete), which has high compressive and tensile strength as well as high durability compared to ordinary concrete. The test program included the studs with a diameter of 16mm and 22mm for various aspect ratios (height to depth ratio of a stud) and cover depths. This paper presents the main results of the experimental investigations.

In the application of Ultra High Performance Concrete (UHPC) to PSC girders by using the post-tensioning system, the high strength and ductility of UHPC in tension can be exploited to substitute the confined reinforcing bars which control the rupture around the anchorage device. The exploitation of such properties is expected to simplify the reinforcing details around the anchorage zone. Taking advantage of UHPC can downsize a cross section with the attributes of high compression and tensile strength. This paper reports the local behavior of UHPC anchor block under compression. Test specimens were made based on mix proportion of K-UHPC (KICT-Ultra High Performance Concrete) developed by the Korea Institute of Construction Technology (KICT). The performance of the anchor block was evaluated according to ETAG-013 (European Technical Agreement Guide No.13) of EOTA (European Organization for Technical Approvals). As the results of the experiment, it is found that the details and reinforcement of UHPC anchorage zone can be simplified with the interconnection effect and the high intensity of the matrix itself.

This work examines the feasibility for estimating existing tensile stress on a stressed wire using the permeability of magnetic flux. A closed magnetic circuit has been constructed to induce magnetic flux inside a steel wire. With different tension stress levels on a wire, the permeability of magnetic flux on the wire has been measured. Two different experimental case studies have been conducted for the examination of sensitivity of permeability of magnetic flux on the stressed wire. One is a varying-length stress test, and the other is a fixed-length stress test. The results show that the permeability of magnetic flux in the varying-length stress test is inversely proportional to the applied stress, while the permeability in the fixed-length stress test is linearly proportional to the applied stress on the stressed wire. It is thus expected that the permeability of magnetic flux on a wire can be a promising indicator for the inspection of its tensile stress.