Numerical Analysis and Load-Carrying Capacity Estimation of Reinforced Concrete Slab Culvert Rehabilitated with a Grouted Corrugated Steel Plate

Li Bai-Jian,Fu Wen-Qiang,Fu Xin-Sha,Huang Yan 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4

Two laboratory tests were conducted to investigate the mechanical properties and develop a load-carrying capacity estimation method for reinforced concrete (RC) slab culverts rehabilitated with a grouted corrugated steel plate (CSP). Subsequently, 216 numerical models of RC slab culverts rehabilitated with different shapes of CSPs and grout strengths were established to investigate the influence of these parameters and the arch effect on the rehabilitated system. A mechanical model was proposed based on the elastic center method, and a load-carrying capacity estimation method of RC slab culverts rehabilitated with grouted CSPs was established and verified. It was concluded that the load-carrying capacity of the rehabilitated system increased with a decrease in the radius of the side walls and crown at a constant radius of the CSP haunch. At a constant radius of the side walls and CSP crown, the load-carrying capacity of the rehabilitated system increased with an increase in the haunch radius. The most effective way to improve the load-carrying capacity of the rehabilitated system was to increase the radius of the haunches and reduce the radius of the arch crown and side wall. The arch effect of the grout was related to the load type. The load-carrying capacity of the rehabilitated system was the highest when the CSP was similar to or the same as the arch axes of the grout. The most important function of the grout was to provide strong lateral restraint for the CSP, reducing the required span and improving the load-carrying capacity of the CSP. In addition, the shear strength of the grout contributed to improving the load-carrying capacity by exerting an arch effect or experiencing shear failure. The proposed load-carrying capacity estimation method is applicable to rehabilitated systems with a box or arch-type CSP. Our findings provide guidance for engineers to design similar rehabilitated systems.

윤중 변동을 고려한 고속철도 교량의 내하력 평가방법 개선방향

이희현,전준창,김만철,이진석 한국철도학회 2020 한국철도학회논문집 Vol.23 No.9

Wheel loads induced by running of KTX trains were measured on eight high-speed railway bridges with ballasted track, and distribution characteristics of wheel loads were analyzed. A method for assessing load carrying capacity of railway bridges, considering the influence of wheel load variations, was proposed. In addition, capacity assessment using measured dynamic wheel loads was performed to examine the effects of variations on capacity evaluation results. In the present study, it was found that wheel loads measured when KTX trains are running are in the range of 0.54 to 1.33 compared to existing wheel load applied to load carrying capacity evaluation, and follow a normal distribution. The existing method, which does not take into account wheel load variations may overestimate (up to about 17%) or underestimate (up to about 23%) the actual load carrying capacity. Therefore, it is appropriate to use the revised response modification factor proposed in this study, which reflects the influence of wheel load variations, to evaluate the load carrying capacity of railway bridges.

전단응력하의 무한체내 타원체불균질물의 균열손상에 따른 하중부하능력의 변화와 탄성응력분포

조의일,박상규 여수대학교 1998 論文集 Vol.12 No.2

In particle or short-fiber reinforced composites, cracking of the reinforcements is a significant damage mode because the broken reinforcements lose load carrying capacity. This paper deals with elastic stress distributions and load carrying capacity of intact and cracked ellipsoidal inhomogeneities. Three dimensional finite element analysis has been carried out on intact and broken ellipsoidal inhomogeneities in an infinite body under pure shear. For the intact inhomogeneity, as well known as Eshelby(1957) solution, the stress distribution is uniform in the inhomogeneity and non-uniform in the surrounding matrix. On the other hand, for the broken inhomogeneity, the stress in the region near crack surface is considerably released and the stress distribution becomes more complex. The average stress in the inhomogeneity represents its load carrying capacity, and the difference of average stresses between the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The load carrying capacity of the broken inhomogeneity is expressed in terms of the average stress of the intact inhomogeneity and some coefficients. It is found that the broken inhomogeneity with higher aspect ratio still maintains higher load carrying capacity.

고속철도 PSC BOX 거더 교량의 내하력 평가에서 재하조건에 따른 충격계수의 차이 분석

최준혁(Junhyeok Choi) 한국방재학회 2023 한국방재학회논문집 Vol.23 No.1

In this study, the load carrying capacity was evaluated using the results of the dynamic load test, instead of the static load test of the field, in the precision safety diagnosis of a high-speed railway PSC BOX girder bridge, and the differences in the impact factor of the bridge according to the load condition of the train and the configuration of the bridge were compared. The impact factor of the bridge was obtained from the measured displacement response via static and dynamic tests for the precision safety diagnosis performed on high-speed railway bridges. The analysis conditions included the location of the sensor, running track of the train, type and span of the bridge, and load condition of the dynamic load test train, test running train, and service train. Consequently, when the impact factor was calculated based on the displacement response of the test running train, instead of the static load test in the load capacity evaluation of the bridge, a difference of -4.96-5.93% was obtained in comparison with the calculation based on the displacement response of the static load test; this corresponds to 0.943-1.053 times the basic load-carrying capacity rate, indicating a difference from the load-carrying capacity rate obtained by the static load test. 본 연구에서는 고속철도 교량의 정밀안전진단에서 현장재하시험의 정적재하시험 대신에 동적재하시험에 의한 결과를 이용하여 내하력을 평가하는 경우 교량의 구성 및 열차의 하중조건에 따른 충격계수의 차이를 비교분석하였다. 교량의 충격계수는 고속철도 교량을 대상으로 수행된 정밀안전진단 시험결과의 정적시험 및 동적시험에 의한 교량의 실측변위응답으로부터 구하였다. 분석조건은 센서의 위치와 열차의 주행선로, 교량의 형식과 지간, 동적주행시험열차, 시험운행열차 그리고 상시운행열차의 주행의 재하조건이다. 그 결과, 교량의 내하력 평가에서 정적재하시험 대신 시험운행열차의 변위응답을 기준으로 충격계수를 산정할 경우 정적재하시험 변위응답을 기준으로 계산한 것에 비하여 -4.96~5.93%의 차이가 발생하였다. 이 값은 기본내하율로 계산하면 0.943~1.053배로서 정적재하시험에 의한 내하율과 차이가 있음을 나타낸다.

Structural performance of novel SCARC column under axial and eccentric loads

Chunheng Zhou,Zongping Chen,Junhua Li,Liping Cai,Zhenhua Huang 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.5

A novel spiral confined angle-steel reinforced concrete (SCARC) column was developed in this study. A total of 16 specimens were prepared and tested (eight of them were tested under axial loading, the other eight were tested under eccentric loading). The failure processes and load-displacement relationships of specimens under axial and eccentric loads were examined, respectively. The load-carrying capacity and ductility were evaluated by parametric analysis. A calculation approach was developed to predict the axial and eccentric load-carrying capacity of these novel columns. Results showed that the spiral reinforcement provided enough confinement in SCARC columns under axial and low eccentric loads, but was not effective in that under high eccentric loads. The axial load-carrying capacity and ductility of SCARC columns were improved significantly due to the satisfactory confinement from spirals. The outer reinforcement and other construction measures were necessary for SCARC columns to prevent premature spalling of the concrete cover. The proposed calculation approach provided a reliable prediction of the load-carrying capacity of SCARC columns.

Coupling Effect of Nodal Deviation and Member Imperfection on Load-Carrying Capacity of Single-Layer Reticulated Shell

Hui-jun Li,Yoshiya Taniguchi 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3

Single-layer reticulated shell is sensitive to imperfections. To clarify the eff ect of member imperfection, nodal deviation and their couplings on load-carrying capacity of reticulated shell, the equivalent load method (ELM) is developed in the present study to establish single-layer reticulated shell with random member imperfection, and its realization procedures in FEM package are well-elaborated. The main conclusions are summarized as follows: the proposed ELM is of high effi ciency to form member imperfection in space structures. For reticulated shell only with member imperfection, the limit load is more or less infl uenced by member imperfection. With the increase of amplitude of member bow imperfection, limit load gradually decreases. Load-carrying capacity of reticulated shell with larger amplitude of bowed member is more sensitive to bending direction of bowed member than the one with smaller amplitude. Load-carrying capacity of the reticulated shell considered is extremely sensitive to nodal deviation. For reticulated shell with nodal deviation and member imperfection, the eff ect of member imperfection on load-carrying capacity is closely related to the magnitude of nodal deviation. Loadcarrying capacity of shell with smaller nodal deviation is obviously aff ected by member imperfection, while not sensitive to member imperfection for reticulated shell with larger one. Member imperfection can be neglected when nodal deviation is large enough. Load-carrying capacity of reticulated shell is also infl uenced by bending angle of bowed member. On the whole, load-carrying capacity of reticulated shell with larger amplitude of member imperfection is more sensitive to bending direction than the reticulated shell with smaller one.

벨트트러스를 사용한 철골 모멘트골조의 하중지지능력 평가

김정환 ( Jung Hwan Kim ),정시정 ( Jung Si Jung ),최재혁 ( Jae Hyouk Choi ) 조선대학교 공학기술연구원 2011 공학기술논문지 Vol.4 No.1

Recently, some building structure have been collapsed because of losses of vertical load carrying capacities occured from accidental events. Even, if buildings are partially damaged by accidental event that have not been foreseen, a specific design technique, by which the damage does not cause fatal gravitational collapse or progressive collapse. however, technique to improve load carrying capacities efficiently are required. Consequently, in this study limit analysis is an example of collapse case resulting from a vertical load. Also we considered a change progress of load carrying capacity according to circumstances about installation of belt truss It was widely used in horizontal displacement control of building. Then, to analyze an effect from loss of number generated by accidentally externel force which has an effect on load carrying capacity of building.

Load-Carrying Capacity Assessment of Deteriorated Rural Bridge

( Kim Han-joong ),( Kim Jong-ok ),( Yang Seung-ie ) 한국농공학회 2002 韓國農工學會誌 : 전원과 자원 Vol.44 No.7

Most of rural bridges have passed 30 years of age since they were built, which have to support unexpected overload caused by changed design load and excessive amount of transportation. For these rural bridges, repairs and replacements are needed. Even though there have been attempt to estimate the safety of existing bridges deteriorated with major defects, those approaches must rely on the observable damage and subsequent decisions are made subjectively. To avoid the high cost of rehabilitation, the bridge rating must correctly represent the present load-carrying capacity. Rating engineers use a methods such as Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance method is suggested instead of the bridge replacement.

교량의 내하력 평가 및 농로교의 하중시험

양승이 ( Yang Seung-ie ),김한중 ( Kim Han-joong ),김진성 ( Kim Jin-sung ) 한국구조물진단유지관리공학회 2003 한국구조물진단유지관리공학회 논문집 Vol.7 No.1

20, 30 년 전 시골지역에 건설된 교량들은 과도한 교통량의 증가에 따른 초과하중을 지탱해야한다. 이러한 교량들에 대해서 보수 보강이나, 교량의 교체가 필요하다. 고가의 보수 보강을 피하기 위해는, 현재 교량의 내하력을 정확히 알아야한다. 내하력 평가자들은 교량의 내하력을 평가하기 위해 허용응력법, 강도설계법, 그리고 하중저항계수법등을 사용한다. 본 연구에서는, 내하력 평가방법을 설명하고, 문헌조사를 통해 교량의 하중실험 자료의 이용에 대하여 설명한다. 그리고, 30년전에 시골지역에 건설된 교량에 대해 하중실험을 하였다. 시험자료로 부터, 교량의 교체를 대신한 새로운 보수보강 방법이 제시되었다. The bridges, which were built between 20 and 30 years ago in rural area, have to support unexpected overload caused by excessive amount of transportation. For these rural bridges, repairs and replacements are needed. To avoid the high cost of rehabilitation, the bridge rating must correctly report the present load-carrying capacity. Rating engineers use Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance strategy is suggested instead of the bridge replacement.

Load-carrying capacity degradation of reinforced concrete piers due to corrosion of wrapped steel plates

Hanbin Ge,Shengbin Gao,Toyoki Ikai,Jie Ni 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.1

Two-dimensional elastoplastic finite element formulation is employed to investigate the load- carrying capacity degradation of reinforced concrete piers wrapped with steel plates due to occurrence of corrosion at the pier base. By comparing with experimental results, the employed finite element analysis method is verified to be accurate. After that, a series of parametric studies are conducted to investigate the effect of corrosion ratio and corrosion mode of steel plates located near the base of in-service pier P2 on load-carrying capacity of the piers. It is observed that the load-carrying capacity of the piers decreases with the increase in corrosion ratio of steel plates. There exists an obvious linear relationship between the load-carrying capacity and the corrosion ratio in the case of even corrosion mode. The degradation of load-carrying capacity resulted from the web's uneven corrosion mode is more serious than that under even corrosion mode, and the former case is more liable to occur than the latter case in actual engineering application. Finally, the failure modes of the piers under different corrosion state are discussed. It is found that the principal tensile strain of concrete and yield range of steel plates are distributed within a wide range in the case of slight corrosion, and they are concentrated on the column base when complete corrosion occurs. The findings obtained from the present study can provide a useful reference for the maintenance and strengthening of the in-service piers.