• Advances in concrete construction
• /
• 제9권3호
• /
• pp.235-248
• /
• 2020

Progressive collapse in a structure occurs when load bearing members are failed and the adjoining structural elements cannot resist the redistributed forces and fails subsequently, that leads to complete collapse of structure. Recently, construction using precast concrete technology is adopted increasingly because it offers many advantages like faster construction, less requirement of skilled labours at site, reduced formwork and scaffolding, massive production with reduced amount of construction waste, better quality and better surface finishing as compared to conventional reinforced concrete construction. Connections are the critical elements for any precast structure, because in past, major collapse of precast structure took place because of connection failure. In this study, behavior of four different precast wet connections with U shaped reinforcement bars provided at different locations is evaluated. Reduced 1/3^rd scale precast beam column assemblies having two span beam and three columns with removed middle column are constructed and examined by performing experiments. The response of precast connections is compared with monolithic connection, under column removal scenario. The connection region of test specimens are filled by cast-in-place micro concrete with and without polypropylene fibers. Performance of specimen is evaluated on the basis of ultimate load carrying capacity, maximum deflection at the location of removed middle column, crack formation and failure propagation. Further, Finite element (FE) analysis is carried out for validation of experimental studies and understanding the performance of structural components. Monolithic and precast beam column assemblies are modeled using non-linear Finite Element (FE) analysis based software ABAQUS. Actual experimental conditions are simulated using appropriate boundary and loading conditions. Finite Element simulation results in terms of load versus deflection are compared with that of experimental study. The nonlinear FE analysis results shows good agreement with experimental results.

• Structural Engineering and Mechanics
• /
• 제26권2호
• /
• pp.211-229
• /
• 2007

An experimental investigation to determine the transfer length of a seven-wire prestressing strand in different concretes is presented in this paper. A testing technique based on the analysis of bond behaviour by means of measuring the force supported by the prestressing strand on a series of specimens with different embedment lengths has been used. An analytical bond model to calculate the transfer length from an inelastic bond stress distribution along the transfer length has been obtained. A relationship between the plastic bond stress for transfer length and the concrete compressive strength at the time of prestress transfer has been found. An equation to predict the average and both the lower bound and the upper bound values of transfer length is proposed. The experimental results have not only been compared with the theoretical prediction from proposed equations in the literature, but also with experimental results obtained by several researchers.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.802-805
• /
• 2007

The exhaust system, including a muffler, is one of the major sources to generate the radiated noise of construction equipment. The muffler is generally known that it reduces the exhaust noise level, but it sometimes increases the noise level because of the flow effect inside a muffler. So, it is required to consider the flow effect inside a muffler to reduce the exhaust noise level of construction equipment. In this paper, an experimental method to consider a quantitative flow effect inside a muffler was set up through a series of tests. Finally, the experimental result was verified through the flow noise analysis using CFD analysis result. These results make it possible to understand the dynamic characteristics of the flow noise and to design the low noise muffler for the construction equipment.

• Computers and Concrete
• /
• 제13권4호
• /
• pp.501-516
• /
• 2014

The purpose of this study was to investigate the performance of precast concrete pier cap system. The proposed precast pier cap provides an alternative to current cast-in-place systems, particularly for projects in which a reduced construction time is desired. Five large-scale pier cap specimens were constructed and tested under quasistatic monotonic loading. The computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology) was used for the analysis of reinforced concrete structures. A bonded tendon element is used based on the finite element method, and can represent the interaction between the tendon and concrete of a prestressed concrete member. A joint element is used in order to predict the inelastic behaviors of segmental joints with a shear key. This study documents the testing of the precast concrete pier cap system under monotonic loading and presents conclusions and design recommendations based on the experimental and analytical findings. Additional full-scale experimental research is needed to refine and confirm design details, especially for actual detailing employed in the field.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 가을학술발표대회논문집
• /
• pp.197-198
• /
• 2023

Construction waste takes about 50% of total industrial waste. Researchers focuses to decrease the amount of construction waste by recycling the waste during the construction site. However, research about recycling the gelatin-sand composite is not yet been studied. This research is an experimental research on recycling the total specimen of gelatin-sand composite. Two methods were held when making the 2^nd generation of the gelatin-sand specimen. As a result, there was no difference in flexural strenght between two different method of 2^nd generation of specimen. However, the second method of 2^nd generation showed about 20% higher compressive strength than the first method.

• 한국실내디자인학회논문집
• /
• 제16권3호
• /
• pp.3-9
• /
• 2007

Taliesin West is a meaningful historic site in architecture field, because its place had still been existing only one in the world as a ideal architectural community for working and living as well as learning by doing for Taliesin Fellowships and others based on F. L. Wright's idea of Organic Architecture. The main purpose of this study was to follow up the architectural thought and its construction shown in F. L. Wright's 'Taliesin West'. A study on the key notes are as follows; 1) The key-clue of the construction background for Taliesin West was based on the project of 'Complex Campus Building' which was early planed by F. L. Wright. 2) A basic design idea for Taliesin West was admiring from its own site characters as well as the Experimental construction methods and materials. 3) Design motive of Taliesin West was based on American Indian's movable shelter which called 'Tepee.' 4) A construction of F. L. Wright's temporary studio, Ocotilla, was a good opportunity to construct for Taliesin West which construction methods, covered and framed, were same as Ocotilla. 5) A concept idea of the master plan for Taliesin West came from combining Taliesin's Hillside Home School and Complex Campus Building project. 6) Construction of Taliesin West was a final accomplished place as F. L. Wright's utopia architecture and community.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.697-706
• /
• 2011

There are more than 800 railway steel plate girder bridges which are in use and the total length is approximately 50 km. Among these, it shall be pointed out that non-ballast rail systems which lay on wood sleepers are the most critical members. To strengthen this type of structures, mainly two methods have been applied. The first one is the most typical method which is to replace the girders with slab girder system or steel composite girders and to add ballast. It is not uncommon that the construction cost of substructure is more than ten time higher than that of superstructures and even in this case, the structural uncertainty for the substructures is not diminished. To resolve above mentioned problems, new method was developed to rehabilitate railway steel girder bridge by adding PC-slab using transport equipment. Using this method, substructure strengthen is rarely required because the additional weight to the bridge superstructure is only up to 1.0t/m. Also it was possible to save the construction cost by reducing construction duration and by simplifying the construction process. Experimental construction was performed for Jewon bridge and measurements were performed before and after construction to verify the bridge capacity.

• Structural Engineering and Mechanics
• /
• 제38권2호
• /
• pp.141-156
• /
• 2011

A cable stayed bridge under construction has low structural damping and is not as stable as the completed bridge. Control countermeasures, such as the installation of energy dissipating devices, are thus required. In this study, the general procedure and key issues on adopting an active control device, the active mass damper (AMD), for vibration control of cable stayed bridges under construction were studied. Taking a typical cable stayed bridge as the prototype structure; a lab-scale test structure was designed and fabricated firstly. A baseline FEM model was then setup and updated according to the modal parameters measured from vibration test on the structure. A numerical study to simulate the bridge-AMD control system was conducted and an efficient LQG-based controller was designed. Based on that, an experimental implementation of AMD control of the transverse vibration of the bridge model was performed. The results from numerical simulation and experimental study verified that the AMD-based active control was feasible and efficient for reducing dynamic responses of a complex structural system. Moreover, the discussion made in this study clarified some critical problems which should be addressed for the practical implementation of AMD control on real cable-stayed bridges.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회(2)
• /
• pp.1126-1127
• /
• 2005

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2003년도 학술.기술논문 발표회
• /
• pp.85-89
• /
• 2003

With the social demands for tall building, the level of techniques for construction become high and there are various building materials. Also, the construction system become very complicated with the increase of worker. In spite of above facts, the method of construction management depends on the experimental capacity of a construction manager, and there are many unreasonable elements. These elements prevent well-going in construction process. To solve this problem, it is necessary to make a new system of construction management which is adequate for the condition of company and the contents of construction. In this study, the characteristic of production system and the present condition of construction management were investigated with the help of survey. Thus, the new method of construction management which can clear the previous problems was proposed.