Earticle

An experimental program was initiated to investigate the structural capacity of PC(Precast Concrete) joints used for the underground parking system. Static testing of 14 typical PC joints specimens was conducted. Specimens were designed to span a range of parameters typically encountered for such members, based on findings from the survey of existing PC joint details used in the construction fields in Korea. The specimens were subdivided into 5 groups by their joint types. The specific structural behavior germane to each specimen, and general observations on overall member behavior as a function of the considered parameters, are reported. From the results of tests on 14 PC joints specimens, the PC system used for the underground parking building was found to have similar structural capacities when comparing to the cast-in-place concrete system.

This study shows a variance regularization method in order to obtain the stable optimal solutions, when a numerical method accelerating design variables is used for material topology optimization algorithm. Since a moved and regularized Heaviside function used in the accelerated method is composed of nonlinear concave and convex functions in a given design domain between 0 and 1, design variables below 0.5 can move fast toward the value of 0 and those over 0.5 are rapidly located to the value of 1. However optimal solutions may be not stable due to singularity of element stiffness, while the accelerated design variables are too closed to value 0. In particular this instability may occur to the accelerated method-based material topology optimization algorithms much repeating the moved and regularized Heaviside function. In order to resolve the problem, in this study, a variance regularization is formulated within a linear governing equation for structural analyses of optimization procedures. Numerical examples for topologically optimally modeling a linear elastostatic MBB-beam verify that the accelerated method of design variables take numerical stability of topological optimal solutions by being associated with the variance regularization method.

The technical development of design, construction and the material of construction field are quickly advanced. The structures becomes bigger and high ability because of the reasoning being. Then the importance of the problem regarding heat of hydration is embossed. But the method which gets the temperature stress which occurs because of heat of hydration is difficult and it is strenuous to apply in the construction site which changes at any time. There is the method that able to get thermal cracking index in brief in the concrete standard specifications. But the reliability deteriorates because there is not referring about the time. The thesis is presented amended simply formula that the item regarding a temperature climbing velocity is complemented. The analytical result gives the place help which grasps temperature crack degree each time a design or construction and it is useful in plan of the economic and stable mass concrete structure and with the fact that it will be applied.

This study is concerned with drying shrinkage of polymer-modified mortars according to the tensile stress of polymer film. The purpose of this study is to obtain basic data necessary to develop appropriate latexes for cement modifiers. This paper deals with the effects of polymer film on the drying shrinkage of the polymer-modified mortars. The polymer-modified mortars are prepared with different polymer-cement ratios, and tested for glass transition temperature, elongation and tensile stress of polymer films and drying shrinkage of polymer-modified mortars. From the test results, the glass transition temperature and tensile stress of polymer film is increased remarkably with an increase in the MMA contents. And, the superior drying shrinkage of polymer-modified mortars using MMA/BA latexes is obtained at a bound MMA content of 70 and 80 percent, MMA/EA latexes is obtained at a bound MMA content of 60 percent. Accordingly, it is judged that the polymer-modified mortars with high tensile stress of polymer film can be decreased the drying shrinkage

ructures become more important, and will be emphasized more crucially in the near future. It is also necessary to develop a proper diagnostic evaluation procedure which allows us to better evaluate the deterioration of concrete structure, to inspect the reinforced concrete structure, to determine whether the reinforced structure needs to be demolished or not, and finally to choose proper rehabilitation strategy. In this research, the monitoring system based on previous researches is systematically evaluated. The fundamental research objective is determined based on the evaluation, and actual experiments are performed. Ultimately, the self monitoring apparatus (SMA) system which allows monitoring the service life of the reinforced concrete structure is suggested. The suggested monitoring system (SMA) consists of 1st spacer indicating perceivable material, 2nd spacer indicating protection material, and 3rd spacer indicating cover depth of reinforcing steel. These elements are placed in the reinforced concrete structure as a unified system.

Construction projects include many risks due to uncertain factors, so it is very important to repeatedly evaluate the performance of on-going work in the aspects of cost and schedule plans during a project. In Korea, however, construction projects are managed by focusing on the results of projects. Moreover, cost and schedule are managed separately even though the efficiency of integrated management is very high. So, on the first of July, 2000, the Ministry of Construction and Transportation announced that Earned Value Management System(EVMS) which is a cost and schedule integrated management tool will be applied in the public sector. However, many people confuse the meaning of EVMS with that of cost and schedule management, and they also believe the EVMS isn't suitable for Korea, because the construction environment of Korea is different from that of America and Australia, etc. As a matter of fact, in America Cost/Schedule Control System Criteria(C/SCSC) which is the original form of EVMS was established in 1965, and they have 32 years experience to apply C/SCSC and EVMS to real projects. Also, in America the EVMS is applied to only Cost Plus Fee Construction projects, while on Korea almost all projects are performed by Fixed Price Contract. Accordingly, this study understands and analysis the concepts of cost/schedule integrated management and Baseline establishment method that is a major element of EVMS management system clearly and finally, proposes the establishment method of PMB for owners that could be applicable to real projects.

The objectives of this study are 1)to evaluate PMIS with quality of connections and services among construction processes ,design modeling (eg: architectural, structural, mechanical, and electronic modeling), and documents (eg: specifications, contract document etc), 2)to develop prototype of repository system, for managing interrelations about improved PMIS processes, output of process with evaluations and improvements, These improvements enable 1)construction planning with valid and latest informations, about method of construction, estimation, schedule planning information, budget planning through existing knowledge at the phase of design, 2)and providing to the point, informations and knowledges of each execution processes (such as construction planning/architectural structures/facilities/electrical systems at the phase of execution).