• Steel and Composite Structures
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• v.20 no.6
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• pp.1259-1274
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• 2016

A precast composite column system has been developed in this study by utilizing multi interlocking spiral steel into a centrifugally-formed hollow-core precast (CHPC) column. The proposed hybrid column system can have enhanced performances in the composite interaction behavior between the hollowed precast column and cast-in-place (CIP) core-filled concrete, the lap splice performance of bundled bars, and the confining effect of concrete. In the experimental program, reversed cyclic loading tests were conducted on a conventional reinforced concrete (RC) column fabricated monolithically, two CHPC columns filled with CIP concrete, and two steel-reinforced concrete (SRC) columns. It was confirmed that the interlocking spirals was very effective to enhance the structural performance of the CHPC column, and all the hollow-core precast column specimens tested in this study showed good seismic performances comparable to the monolithic control specimen.

• Steel and Composite Structures
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• v.2 no.5
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• pp.355-378
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• 2002

Use of composite steel construction with precast hollow core slabs is now popular in the UK, but the present knowledge in shear capacity of the headed shear studs for this type of composite construction is very limited. Currently, all the information is based on the results obtained from experimental push-off tests. A finite element model to simulate the behaviour of headed stud shear connection in composite beam with precast hollow core slabs is described. The model is based on finite element method and takes into account the linear and non-linear behaviour of all the materials. The model has been validated against the test results, for which the accuracy of the model used is demonstrated. Parametric studies showing the effect of the change in transverse gap size, transverse reinforcement diameter and in-situ concrete strength on the shear connection capacity are presented.

• Computers and Concrete
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• v.13 no.3
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• pp.389-409
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• 2014

Precast hollow core slabs (HCS) are technically advanced products in the precast concrete industry, widely used in the last years due to their versatility, their multipurpose potential and their low cost. Using three dimensional FEM (Finite Element Method) elements, this study focuses on the stresses induced by the prestressing of steel. In particular the investigation of the spalling crack formation that takes place during prestressing is carried out, since it is important to assure the appropriate necessary margins concerning such stresses. In fact, spalling cracks may spread rapidly towards the web, leading to the detachment of the lower part of the slab. A parametric study takes place, capable of evaluating the influence of the tendon position and of the web width on the spalling stress. Consequently, after an extensive literature review on the topic of soft computing, an optimization of the HCS is performed by means of Genetic Algorithms coupled with 3-D FEM models.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.425-430
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• 1996

The purpose of this study is to investigate the behavior of the bearing precast concrete (pc) wall structure with hollow core based on experimental tests. In order to evaluate the cyclic performance of the pc walls. Too one story pc walls and ond one reinforced concrete wall are made. The experimental results of pc walls were compared with those values of reinforced concrete (rc) wall. The structural behaviors of pc wall structure with hollow core are similar to those of reinforced concrete bearing wall structure. This study shows that the pc wall with hollow core could be treated as rc wall when designs the pc wall structure against lateral loads

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.156-163
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• 2002

Hollow core slabs generally have not been used for a bridge or a parking slab in Korea. In this study, high performance hollow core slabs, which have been the most thick one in domestic are re-designed and examined for practical use. Flexural tests were performed on four 315mm deep hollow core slabs to investigate adaptability for high vehicle live loadings and composite action with topping concrete. The precast slabs were pre-tensioned with ten strands of 1/2 inch diameter at the lower of slab and four strands of 1/2 inch diameter at the upper of slab, and cast with 80 mm deep topping concrete. Tested hollow core slabs showed ductile failure behaviors which were conformed to the current Ultimate Strength Design Method for a span of 10m up to the live load of 1,000 kgf/㎡. The rectangular md round shear cotters which were used for the composite action between precast and topping concrete, developed sufficient strengths because cracking, even micro had not been developed at the end of slabs up to the pure flexural tensile failure.

• Journal of the Korea Concrete Institute
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• v.26 no.5
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• pp.635-642
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• 2014

The weight of concrete could be reduced by using hollow core slabs instead of heavy solid slabs, leading to cost reduction. The long span be also achieved by introducing prestress in hollow core slabs. but the evaluation of shear strength of precast-prestressed hollow core slabs are needed because the cross section is reduced in web and arranging shear reinforcement is not possible. In this study, the shear strength of precast-prestressed hollow core slabs were evaluated based on experimental tests. For this purpose, six full scale specimens were made and tested. The shear strength of the specimens were compared with those evaluated from current design provision(EC2 ACI, EN1168 and AASHTO).

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.167-172
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• 2001

Hollow core slabs generally have not been used for a bridge slab or a parking in Korea. In this study, high performance hollow core slabs, which has been the most thick one in domestic are re-designed and examined for practical use. Flexural tests were performed on four 315mm deep hollow core slabs to investigate adaptability for high vehicle live loadings and composite action with topping concrete. The precast slabs were reinforced with 10-l/2 inch dia-strands at the lower of slab and 4-l/2 inch dia-strands at tile upper of slab, and cast with 80mm deep topping concrete. Those tested hollow core slabs showed ductile failure behaviors which were conform to the current Ultimate Strength Design Method for a span of l0m up to the live load of 1, 000 kg/$m^2$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.94-101
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• 2010

Recently, the interest of precast concrete is increased for rapid construction in construction fields. Experimental study about the shear performance of the joint between hollow core slabs which have internal core to reduce their weight was performed. Main test variables were thickness of the topping concrete and existence of the wiremesh. Total 8 specimens including 4 in-plane shear and 4 out of plane shear were tested. Test results were analyzed in terms of cracking load, failure load, failure aspect, stiffness and ductility, and compared its design load to develop optimum design details. Test results indicated that the shear performance of the non-shrinkage mortar specimen was similar to that of 30mm thickness topping concrete specimen, and the effect of wiremesh reinforcement did not affect the failure load or stiffness of the specimens but the increase of ductility. And this paper presents the comparison results of the test results and design load to provide the optimum detail of the joint design between the hollow core slabs.

• Structural Engineering and Mechanics
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• v.81 no.1
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• pp.59-68
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• 2022

Prestressed prefabricated hollow core concrete slabs with spans of 5 m and 10 m are commonly used since last century and still in service due to the advantage of construction convenience and durability. However, the end slabs are regularly subjected to cracks at the top and fail with brittleness due to the asymmetric boundary conditions. To better maintain such widely used type of hollow core slabs, the effect of asymmetric constraint in the end slabs are systematically studied through detailed nonlinear finite element analyses and experimental data. Experimental tests of slabs with four prestressed tendons and seven prestressed tendons with different boundary conditions were conducted. Results observe three failure modes of the slabs: the bending failure mode, shear and torsion failure mode, and transverse failure mode. Detailed nonlinear finite element models are developed to well match the failure modes and to reveal potential damage scenarios with asymmetric boundary conditions. Recommendations regarding ultimate capacity of the slabs with asymmetric boundary conditions are made to ensure a safe and rational design of prestressed concrete hollow slabs for short span bridges.

• Steel and Composite Structures
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• v.33 no.1
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• pp.111-122
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• 2019

This paper presents an experimental work on the post-fire behavior of two kinds of innovative composite stub columns under eccentric compression. The partially precast steel reinforced concrete (PPSRC) column is composed of a precast outer-part cast using steel fiber reinforced reactive powder concrete (RPC) and a cast-in-place inner-part cast using conventional concrete. Based on the PPSRC column, the hollow precast steel reinforced concrete (HPSRC) column has a hollow column core. With the aim to investigate the post-fire performance of these composite columns, six stub column specimens, including three HPSRC stub columns and three PPSRC stub columns, were exposed to the ISO834 standard fire. Then, the cooling specimens and a control specimen unexposed to fire were eccentrically loaded to explore the residual capacity. The test parameters include the section shape, concrete strength of inner-part, eccentricity ratio and heating time. The test results indicated that the precast RPC shell could effectively confine the steel shape and longitudinal reinforcements after fire, and the PPSRC stub columns experienced lower core temperature in fire and exhibited higher post-fire residual strength as compared with the HPSRC stub columns due to the insulating effect of core concrete. The residual capacity increased with the increasing of inner concrete strength and with the decreasing of heating time and load eccentricity. Based on the test results, a FEA model was established to simulate the temperature field of test specimens, and the predicted results agreed well with the test results.