Applied Mechanics and Materials Vols. 752-753

Abstract: This article presented the analytical results focused on the responses of existing bridges in Thailand subjected to overweight vehicles. The bridges, span lengths ranging from 5 to 20 meters, were loaded by the overweight vehicles with multi-axle loading having gross weight of 400 tons. The rating factors of bridges were also performed. The bridge strengthening methods using carbon fiber reinforcement polymers and intended settlement technique were also presented.The results indicated that the load rating factors were increased and conformed to the load rating standards. The results of this study would be a reference data to establish an alternative plan of bridge strengthening to improve the safety of the bridges under a moving of overweight vehicles.

Abstract: Carrying capacity and fracture modes of concrete beams reinforced by different types of fiber reinforced plastic (FRP) bars are analyzed experimentally and numerically. The four-point-bending test is used as a typical loading case for this purpose. Synchronous registration of loading level, displacements and strains is performed by using InstronTM servohydraulic machine, LVDT sensors, strain gauges and digital image correlation Vic3DTM system. The experimental data and results of finite element simulations are compared and discussed.

Abstract: Developed in 2000, the Taiwan Bridge Management System (TBMS) is an internet-based, nation-wide bridge management system used by all of the bridge management agencies in Taiwan. Currently, the TBMS has an inventory of more than 24,300 bridges with 14 years of visual inspection data and maintenance records. The inspection data of each bridge are input into the TBMS at least once per two years. In order to have a fast assessment of bridge condition in resisting natural disasters and traffic loads, five indices are established in this research: (1) Degree of flood resistance (DF), (2) Degree of mudflow resistance (DM), (3) Degree of earthquake resistance (DE), (4) Degree of loads resistance (DL), and (5) Degree of collapse resistance (DC). Calculation of these five indices is based on the inventory and visual inspection data of each bridge without further thorough site investigation. These indices are used for screening or sieving bridges out of the TBMS inventory that are potentially vulnerable to natural disasters or traffic loads, thus maintenance efforts can be put on such bridges to improve the efficiency of bridge management.

Abstract: Floating floor structures installed with resilient materials are commonly used to reduce sound from floor impacts. Resilient materials minimize the transmission of vibrations by absorbing shock vibrations occurring on the upper part. The floor impact sound reduction performance of resilient materials is related to the dynamic stiffness, which is a physical characteristic of materials. However, the dynamic stiffness varies according to the increase in the loading time of the load that is installed on the upper part of resilient materials. The dynamic stiffness values increase with an increase in the loading time; an increased dynamic stiffness value decreases the vibration reduction effect. The present study focuses on a floor structure installed with resilient materials, and identifies the degree of reduction in floor impact sound insulation performance with the elapse of time. The insulation of sound from lightweight impact sound decreased with the elapse of time, whereas the heavyweight impact sound did not show significant changes.

Abstract: Mechanical property and constraint mechanism of concrete cylinders confined by TRC under uniaxial compression is analyzed. 24 concrete cylinders confined by TRC and 8 unconfined concrete cylinders are loaded under uniaxial compression to investigate the performance based on textile ratio, section dimension and strength of concrete. Based on the test results, stress process and failure mechanism of strengthened members is studied, stress-strain relationship of strengthened members is researched, effect of ratio of textile reinforcement, section dimension and concrete strength on ultimate strength of strengthened members is also evaluated. The results show strengthened members showed increasing in strength and deformation. Strengthened members showed drum-shaped shear damage. With the increasing of textile ratio, the confining effect of TRC on the concrete increases. With the increasing of section dimension, the confining effect of TRC on the concrete decreases. The confining effect of TRC on low strength concrete is stronger.

Abstract: The paper deals with load-carrying capacity of bolted connections subjected to unequal double shears with thin plates as outer members and inner timber member. There are derived equations which describe the load-carrying capacity of this connection type in the ultimate limit state.

Abstract: In the present study, a concrete life-cycle assessment system (CLAS) is developed that can easily and quantitatively assess green-house gas emissions during the production of concrete by applying life-cycle assessment techniques. The CLAS is divided into simple and detailed assessment methods; a database (DB) of a standard mix design and energy consumption amount, and basic green-house units applicable to each method, was constructed. A case assessment using the developed system showed that the green-house gas emission determined by the detailed assessment method differed from that by the simple assessment method by approximately 10%. These results show that the proposed method is suitable for estimating green-house gas emissions related to concrete.

Abstract: Method of using hydroinsulating injection screens during redevelopment of wet masonry is nowadays one of the most efficient methods of treating rising wetness in old but also new buildings. One of the biggest advantages of this method is low damage to the building structure and the possibility of treating the masonry from the inside of the building. One of the aspects that has influence on injection screens functionality is wetness of treated masonry. The main object of this paper is to observe changes in the penetration rate of injection gels in dependence on wetness of building materials.

Abstract: Building designs should be reviewed from the aspects of both design aesthetics and energy performance. The installation of insulation materials in external walls, roofs, and floors is a basic method that could reduce energy losses from buildings. The purpose of this study is to investigate the types of insulation materials selected as building materials and the insulation performance of each building elements when designing new buildings in South Korea. The insulation performance of the external walls, roofs, and floors of buildings were compared with the insulation criteria of the Energy Saving Design Standards of Buildings in building energy code. The design documents, as well as drawings and building energy saving plan sheets, which are required to be submitted for buildings larger than a certain size in South Korea, were collected. The most widely used insulation material in multi-family housings and non-residential buildings was extruded polystyrene (XPS). The insulation performance of external walls, roofs, and floors were higher than that established by design criteria of building energy code. In particular, the external walls had roughly a 25.5% better insulation performance than the insulation criteria.

Abstract: This article presents the results of long-term research of airborne sound insulation of a dividing wall. Specifically it shows how strong effect on the acoustic properties of the dividing walls has the line installation of technical equipment of building. The experimental structure was built from shaped hollow bricks where the influence of structural damage is in terms of the noise propagation essential. This type of structure was selected because it is one of the most commonly used structural systems and the acoustic properties are still neglected aspect.