• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.544-547
• /
• 2004

Predicting the failure modes of reinforced concrete corbels is difficult because the reinforced concrete corbels show the shapes of sudden shear failures at even slight deflection. For this reason, an exact analysis method is demanded highly. In this study, the validity of the grid softened strut-tie model method suggested for concrete member analysis was examined through the ultimate strength evaluation of the reinforced concrete corbels tested to failure. The evaluated ultimate strengths by the grid softened strut-tie model method were compared with those by the ACI 318-02 and the softened strut-tie model method.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.749-752
• /
• 2005

Normally, the degradation of concrete member exposed to fire is largely dependent on the fire scale and fire condition. With all ensuring the fire resistance structure as a method of setting the required cover thickness to fire, the RC is significantly affected from the standpoint of its structural stability that the compressive strength and elastic modulus is reduced by fire. Thus, this study is concerned with experimentally investigating fire resistance of high strength-light weight concrete. From the test result, high strength-light weight concrete is happened explosive spalling. The decrease of cross section caused by explosive spalling made sharp increasing gradient of inner temperature.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1424-1430
• /
• 2007

Corrugated structural plate is ductile structural member which has high sectional properties compared with same thickness of plate. Corrugated plate resists the external forces by the combined action of retained soils and structures. Since it is easy to transport and assemblage of in-situ, the duration and cost of construction can be reduced. Corrugated plate structures, therefore, are widely used in culverts, hydro passages and simple bridges. RC culvert with supported by unstable soil layersin railway construction project of pohang${\sim}$samchuk has been replaced by corrugated plate culvert due to the reduction of construction duration and cost, especially the performance of behavior of settlement of ground. The structural analysis, design processes, and the economic advantages of the corrugated plate culvert are studied in this paper.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.527-532
• /
• 2000

Cracks in reinforced concrete members are important element in structural analysis and design. It is clear from the test results that shear strength of cracked member is remarkably degraded compared with uncracked one. However, considerable amount of shear resistance by such mechanisms as aggregate interlock and dowel action is still active. There are various approaches to shear transfer estimation including finite element analysis, fracture mechanics, upper bound theory of plasticity, etc., but working out comprehensive and consistent models and manageable equations is rather difficult and remains to be improved. Shear transfer problems under cyclic loading and effective compressive strength of cracked concrete have not been adequately investigated and need further systematic research.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.10a
• /
• pp.450-455
• /
• 1997

In recent years the research and development about the new material proceeds rapidly and actively in building industry. We are concerned with high-strength concrete as a new material. As the building structure becomes bigger, higher and more specialized, so does the demand of material and member with high strength for building expands greatly. In the future, we will quite need to research repair and rehabilitation to make high strength concrete structural building for our safe. So, I did an study on carbon fiber sheet rehabilitation(CFSR) of reinforced high strength concrete beams. The carbon fiber reinforced plastic(CFRP) bonding method is widely used for reinforcing the existing concrete structure among the various methods. The test results indicate that CFS is very effective for strengthening the damaged beams and controlling deflections of the repaired beams. When carbon fiber sheet rehabilitation of reinforced high strength concrete beams happened diagonal crack, the increase in the number of CFS layer didn't effect the increase in strength of beams. Also, by changing the CFS stick position gave diversified ultimate load in CFSR beams.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.615-620
• /
• 1998

The objective of this experimental study is to investigate the hysteretic behavior of reinforced concrete piers subjected to quasi-static cyclic loads, which have been used in large numbers for railway and urban transportation facilities. Important test parameters are hoop ratio, axial load, loading type, and the behaviors f members have been evaluated through limit states of crack occurrence, yielding and ultimate state of member, ductility and load-deflection loop can be secured by considering the influence of hoop reinforcement ratio and axial load, and that plastic hinge length and ductility ar determined by the combination of the quantities of hoop reinforcement and axial load.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10b
• /
• pp.885-890
• /
• 2000

12 RC deep beams with a/d = 1.17 are reported. This paper is to study the effect of vertical and horizontal web reinforcement and web reinforcement arrangement on inclined cracking shear, ultimate shear strength, midspan deflection, and inclined crack width. Test results indicated that web reinforcement produces and arrangement seems to moderately affect inclined cracking shear, ultimate shear strength and crack width. However, addition of horizontal web reinforcement(pv = 0.0085) little or no influence on inclined cracking shear, ultimate shear strength and crack width. The member which vertical and horizontal web reinforcement concentrate on the center web considerably increases in load-carrying capacity.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.21-24
• /
• 2006

In recent, there are a lot of problems such as shortage of construction workers, complicate progress of work and so on under RC construction. To solve these problems, the construction methods without form-work are used in the main structural members - beam, slab and stairs. However, there isn't yet form-workless system for columns. The purpose of this study was to experimentally evaluate the structural behavior of full scaled no-form system columns reinforced with steel sheet forms and angles. The main variables are 1) comparison of concrete member strength with and without reinforcement, 2) effect of L-angle.

• Journal of the Korea Concrete Institute
• /
• v.24 no.6
• /
• pp.695-703
• /
• 2012

Recently, major infrastructure such as bridges, tunnels, PCCVs (Prestressed Concrete Containment Vessel), and gas tanks are Prestressed Concrete (PSC) structure types, which improve their safety by using confining effect from prestressing. Generally, concrete is known to be an outstanding fire resistant construction material. Because of this reason, researches related to extreme fire loaded PSC member behaviors are not often conducted even though PSC behavior under extreme fire loading is significantly different than that of ordinary reinforced concrete (RC) behavior. Therefore, in this study, RABT fire loading tests were performed on bi-directionally prestressed concrete panels with $1000{\times}1400{\times}300mm$ dimensions. The prestressed specimens were applied with 430 kN prestressing (PS) force using unbonded PS thread bars. Also, residual strength structural tests of fire tested PSC and ordinary RC structures were performed for comparison. The study results showed that PSC behavior under fire loading is significantly different than that of RC behavior.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.6
• /
• pp.238-245
• /
• 2010

Progressive collapse is defined as a collapse caused by sectional destruction of a structural member which links to other surrounding structures. Currently the design guidelines for the prevention of progressive collapse is not available in Korea. So, structural engineers have a difficulty in evaluating progressive collapse. In this study, the static and dynamic analysis to evaluate the methods and procedures are conducted using commercial analysis program for RC moment resisting frames. According to the study, DCR value of RC moment resisting frame system based on code in Korea is over 2 and it shows that it can't provide alternate load paths due to the progressive collapse. And additional reinforcement should be considered for the progressive collapse resistance. As a result of vertical deflection and DCR value of linear static analysis and linear dynamic analysis, the results of dynamic analysis were underestimated more than the result of static analysis. Thus, the dynamic coefficient value of 2 provides conservative estimation.