Based on the principle of grid shear reinforcement, the concept of precast segmental girders with continuous longitudinal reinforcements across joints was proposed. Three test beams were designed, and the joint type was taken as the test parameter. The bending shear test was carried out with the research objects of crack development, reinforcement strain, failure mode, stiffness and bearing capacity. The test results show that the longitudinal reinforcement of webs across joints effectively bears the axial tension caused by shear force, and plays the same role of shear resistance as the stirrup. The continuous longitudinal reinforcement can restrain the development of oblique cracks and limit the width of main cracks, so as to effectively improve the stiffness of precast segmental beam structure. During the whole loading process from the cracking to the failure of continuous longitudinal reinforcement precast segmental beams, the structure near the joint satisfies the plane cross-section assumption, and the mechanical behavior is similar to that of the whole beam. The test results fully verify the necessity of continuous longitudinal reinforcement across the joint of precast segmental beams.
[1] RABBAT B G, SOWLAT K J. Testing of segmental concrete girders with external tendons [J].PCI Journal,1987, 32(2):86.
[2] HINDII A, MACGREGOR R, KREGER M E, et al. Enhancing strength and ductility of post-tensioned segmental box girder bridges [J].ACI Structural Journal,1995, 92(1):73.
[3] MACGREGOR R, KREGER M E, BREEN J E. Strength and ductility of a three-span externally post-tensioned segmental box girder bridge model [J].Earth Planetary Science Letters,1990, 305(1/2):83.
[4] RAMOS G, APARICIO A C. Ultimate analysis of monolithic and segmental externally prestressed concrete bridges [J].Journal of Bridge Engineering: ASCE,1996, 1(1):10.
[5] APARICIO A C, RAMOS G, CASAS J R. Testing of externally prestressed concrete beams [J].Engineering Structures,2002, 24(1):73.
[7] HUANG Z, LIU X. Modified skew bending model for segmental bridge with unbonded tendons [J]. Journal of Bridge Engineering,2006, 11(1):59.
[8] YUAN A, DAI H, SUN D, et al. Behaviors of segmental concrete box beams with internal tendons and external tendons under bending [J].Engineering Structures,2013, 48:623.
[9] JIANG H, CAO Q, LIU A, et al. Flexural behavior of precast concrete segmental beams with hybrid tendons and dry joints [J].Construction and Building Materials,2016, 110:1.
[10] JIANG H, LI Y, LIU A, et al. Shear behavior of precast concrete segmental beams with external tendons [J].Journal of Bridge Engineering,2018, 23(8):04018049.
[11] MOUSTAFA S E. Ultimate load test of a segmentally constructed prestressed concrete, I:beam [J]. PCI Journal,1974, 19(4):54.
[12] RAMIREZ G, MACGREGOR R, KREGER M E. Shear strength of segmental structures[C]//Proceedings of the Workshop AFPC External Prestressing in Structures. Sceaux:[s.n.], 1993: 287-296.
[13] TURMO J, RAMOS G, APARICIO A C. FEM study on the structural behaviour of segmental concrete bridges with unbonded prestressing and dry joints: simply supported bridges [J].Engineering Structures,2005, 27(11):1652.
[14] TURMO J, RAMOS G, APARICIO A C. Shear strength of dry joints of concrete panels with and without steel fibres: application to precast segmental bridges [J].Engineering Structures,2006, 28(1):23.
[15] TURMO J, RAMOS G, APARICIO A C. FEM modelling of unbonded post-tensioned segmental beams with dry joints [J].Engineering Structures,2006, 28(13):1852.
[17] LI G, YANG D, YU L. Combined shear and bending behavior of joints in precast concrete segmental beams with external tendons [J].Journal of Bridge Engineering,2013, 18(10):1042.
[18] BRENKUS N R, WAGNER D J, HAMILTON H R. Experimental evaluation of shear strength of an innovative splice for prestressed precast concrete girders [J].Journal of Bridge Engineering,2016, 21(6): 04016018.
[19] TAKEBAYASHI T, DEEPRASERTWONG K, LEUNG Y W J. A full-scale destructive test of a precast segmental box girder bridge with dry joints and external tendons [J].Structures & Buildings,2015, 104(3):297.
[20] SIVALEEPUNTH C, NIWA J, NGUYEN D H, et al. Shear carrying capacity of segmental prestressed concrete beams [J].Doboku Gakkai Ronbunshuu E: JSCE, 65(1):63.
[21] 中华人民共和国交通运输部. 公路钢筋混凝土及预应力混凝土桥涵设计规范: JTG 3362―2018[S]. 北京; 人民交通出版社,2018.Ministry of Transport of the People’s Republic of China. Specification for design of highway reinforced concrete and prestressed concrete bridges and culverts: JTG 3362―2018 [S]. Beijing:People’s Communications Press, 2018.