• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.288-293
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• 2008

The standard prestressed concrete I-girder bridge (PSC I-girder bridge) is one of the most prevalent types for small and medium bridges in Korea. When determining the member forces in a section to assess the safety of girder in this type of bridge, the general practice is to use the simplified practical equations or the live load distribution factors proposed in design standards rather than the precise analysis through the finite element method or so. Meanwhile, the live load distribution factors currently used in Korean design practice are just a reflection of overseas research results or design standards without alterations. Therefore, it is necessary to develop an equation of the live load distribution factors fit for the design conditions of Korea, considering the standardized section of standard PSC I-girder bridges and the design strength of concrete. In this study, to develop an equation of the live load distribution factors, a parametric analysis and sensitivity analysis were carried out on the parameters such as width of bridge, span length, girder spacing, width of traffic lane, etc. Then, an equation of live load distribution factors was developed through the multiple linear regression analysis on the results of parametric analysis. When the actual practice engineers design a bridge with the equation of live load distribution factors developed here, they will determine the design of member forces ensuring the appropriate safety rate more easily. Moreover, in the preliminary design, this model is expected to save much time for the repetitive design to improve the structural efficiency of PSC I-girder bridges.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.109-120
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• 2001

Live load data were collected with a systematic manner from a survey of a refrigeration stores. Using the collected floor live load survey data, the basic statistics, a histogram of the uniformly distributed loads, and the equivalent uniformly distributed loads are computed for various structural members. Based on the above results, the maximum values of a combined live loads during the design life have been estimated and compared with current design live loads. The ultimate goals of this study are to develop probabilistic live load models to analyze survey data of domestic refrigeration stores, and to propose design live loads for structural types.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.865-870
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• 2001

An effective live load model for analyzing probable maximum live load effects in longitudinal direction such as moment and shear was developed. The main procedure of this live load model is composed of two parts. Firstly, determination of the appropriate influence lines, and secondly, application of the characteristics of vehicles and traffic patterns. Through this procedure, probabilistic distributions of maximum probable load effects are deduced in the form of probability density function (PDF) or cumulative density function (CDF). The proposed live load model is not limited by bridge types(number of spans or girders) and can consider local or global deterioration of bridges in the analysis. Besides, load effects can be determined at any section without restrictions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.25-28
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• 1989

Live load data in domestic office buildings have been collected in a systematic manner. Based on surveyed data, equivalent uniformly distributed load intensities, which produce the same load effect as the actual spatially varying live load, have been obtained for various structural members(such as slab, beam, column, etc.). Influence surface method has been employed to compute load effects under real live load, inclucing beam moment, slab moment as well as axial force and moments in column. The results have been examined to find probabilistic characteristics and relationship between influence area and load intensity(or coefficient of variation). The results were also compared with other survey results and found to be reasonable.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.7-10
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• 2008

Heat release characteristics of live fire load are an important parameter for performance oriented fire safety design of a building. While investigations have been carried out on the fire load and its burning behavior in office, residential and commercial buildings and so on, little effort has been paid for the rational treatment of fire load in post office buildings in Japan. In this report, burning behavior of typical combustible objects in post office buildings are studied by measuring heat release rates of plastic palettes with and without postal envelopes or packages and special containers loading numbers of palettes. The test results suggest that dynamic heat release rate is highly dependent on the condition of palettes especially if they load appropriate amount of postal envelopes or not.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.212-221
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• 2022

In this paper, the evaluation procedure applying the limit state design method is studied to be consistent with the newly issued bridge design code in Korea. The live load factor for evaluation is proposed by calibrating for the target reliability index through reliability analysis. Using the actual bridge information collected for the representative bridge types in Korea, the load effects of the design live loads for the previous and current design codes are calculated and compared. The live load factor is calibrated through reliability analysis using the minimum required strength which equals to the load effect obtained for the example bridge. Bridge evaluation is performed by applying the live load factors for the evaluation level as well as design level. The load rating result is generally increased by applying the limit state design method compared to the previous design method and applying the proposed load factor for lowered target reliability index further increased the rating result.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.859-864
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• 2001

An effective live load model for analyzing probable maximum live load effects such as moment and shear in transverse direction was developed. The main procedure of this live load model is composed of four parts, i.e., firstly, determination of the appropriate influence lines in longitudinal direction, secondly, application of the characteristics of vehicles and traffic patterns in longitudinal direction, thirdly, determination of the appropriate influence lines in transverse direction, and fourthly, application of the characteristics of vehicles and traffic patterns in transverse direction. Through this procedure, the probabilistic distributions of maximum probable load effects are deduced in the form of probability density function (PDF) and/or cumulative density function(CDF). This live load model is able to consider local or global deterioration of bridges in the structural analysis.

• Computational Structural Engineering
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• v.3 no.1
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• pp.109-116
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• 1990

Live load data in domestic office buildings have been collected in a systematic manner. Based on surveyed data, equivalent uniformly distributed load intensities, which produce the same load effect as the actual spatially varying, live load, have been obtained for various structural members (such as slab, beam, column, etc. ). Influence surface method has been employed to compute load effects under real live load, including beam moment, slab moment as well as axial force in column. The results have been examined to find probabilistic characteristics and relationship between influence area and load intensity (or coefficient of variation). The results were also compared with other survey results and found to be reasonable. Based on the probabilistic load models obtained, the lifetime extreme values have been analyzed and compared with current design loads. Tentative equations applicable to decide more rational design loads are also suggested as functions of influence area.

• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.749-765
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• 2021

Suspension bridges bear large eccentric live loads in rush hours when most vehicles travel in one direction on the left or right side of the bridge. With the increasing number and weight of vehicles and the girder widening, the eccentric live load effect on the bridge behavior, including bending and distortion of the main girder, gets more pronounced, even jeopardizing bridge safety. This study proposes an analytical algorithm based on multi-catenary theory for predicting the suspension bridge responses to eccentric live load via the nonlinear generalized reduced gradient method. A set of governing equations is derived to solve the following unknown values: the girder rigid-body displacement in the longitudinal direction; the horizontal projection lengths of main cable's segments; the parameters of catenary equations and horizontal forces of the side span cable segments and the leftmost segments of middle span cables; the suspender tensions and the bearing reactions. Then girder's responses, including rigid-body displacement in the longitudinal direction, deflections, and torsion angles; suspenders' responses, including the suspender tensions and the hanging point displacements; main cables' responses, including the horizontal forces of each segment; and the longitudinal displacement of the pylons' tower top under eccentric load can be calculated. The response of an exemplar suspension bridge with three spans of 168, 548, and 168 m is calculated by the proposed analytical method and the finite element method in two eccentric live load cases, and their results prove the former's feasibility. The nonuniform distribution of the live load in the lateral direction is shown to impose a greater threat to suspension bridge safety than that in the longitudinal direction, while some other specific features revealed by the proposed method are discussed in detail.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.119-120
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• 2009

The Live load distribution factors currently used in the standard prestressed concrete I-girder bridge are just a reflection of overseas design standards. Therefore, it is necessary to develop an equation of the live load distribution factors fit for the design conditions of Korea, considering the standardized section and the design strength of concrete. In this study, the major variables to determine of distribution factors were selected and an equation of live load distribution factors was developed.