This paper presents an evaluation of the tensile strength of an expansion anchor whose anchorage design can cause a fracture on concrete. Tests of heavy-duty anchor and wedge anchor, domestically manufactured and installed in a plain concrete member, were conducted to test the effects of embedment depth and edge distance. A design of post-installed steel anchors termed as the Concrete Capacity Design (CCD) approach, is presented. This approach is compared to the well-known provision, ACI 349-90. The two methods are compared in terms of their effectiveness in predicting the concrete fracture load of an expansion anchor in plain concrete under monotonic loading for important applications. Based on the results of the experiments, for the CCD method, a normalization coefficient of 10.5 is appropriate for the nominal concrete breakout strength of an anchor or group of anchors in tension.
In RHS column to beam connection, when a joint panel part is welded with a through diaphragm, angular distortion of through diaphragm and longitudinal shrinkage of RHS column occur. In this study, a series of measurement of welding deformation of through diaphragm is conducted to investigate the effects of dimensions of connections. Finally, empirical formulae to evaluate the welding deformation are proposed.
In this paper, the damping characteristics of the Old Tacoma Narrows Bridge which was collapsed in 1940 by wind is discussed based on the energy evaluation method. The damping values of the destroyed bridge are analyzed to grasp the contribution of dissipation energy from each construction components of the bridge. The structural damping is also discussed by using loss factors of the steel bridge which was identified by full scale measurements. From these calculation results, some pieces of useful information for the damping characteristics are obtained to reconsider the aerodynamic stability of the Old Tacoma Narrows Bridge.
This paper presents a simple response evaluation method of steel frames with stud-type damper composed by visco-elastic material and two steel columns. In order to obtain earthquake response of the system correctly, a detailed analysis model may be preferred. However, this analysis requires so much amount of time that simple response evaluation method is proposed. The method is based on the damping factor and the damper deformations. The validity of the proposed method is verified by comparing with earthquake response analysis result of the detailed model.
Buckling tests were conducted on concrete filled tube using high tensile strength steel and high strength light-weight concrete. The test results showed that the increase of axial load bearing capacity of the light-weight concrete due to the effect of confinement is not expected even if slenderness is low, and that it is possible to evaluate the buckling strength in current methods if only the effect of confinement is ignored.
This paper will introduce details of seismic retrofitting works done for gable roof framed gymnasiums of elementary schools and of junior high schools which were constructed from 1971 to 1981 in Maizuru city, Japan. Each of these gymnasiums is of gable roof frame with columns and beams made of H-sections. Structural safety inspections revealed that they have serious welding defects at their beam-to-column connections, which required structural reinforcement. The reinforcement was pressing because it was neces sary not only for seismic safety but also for the purpose of providing for heavy snowfall; and so all the steps of the reinforcing works were completed within an extremely short period.
Properties of beams with reduced flange width optimized for maximum plastic energy dissipation are investigated by physical loading test and finite element analysis. It is shown that the strain at the beam-column joint is successfully reduced, and the region of maximum strain is shifted to the area of the reduced width, and the maximum strain at the joint can be controlled by modification of flange shape. Good agreement is obtained between the responses of experimental and numerical results.
Several T-shaped welded joint models are analyzed by finite element method for low cycle fatigue assessment in this paper. Joint is subjected to random loading blocks and strain history is counted by range pair-range counting method. Endeavor is exerted to correlate local strain range of coarse FE model that ignores the weld toe profile with strain range obtained by fine FE model that simulates toe profile. Other parameters such as main geometrical parameters, material properties and loading pattern are also taken into account. After that, strain range relationship is established. Numerical results show that weld toe radius is the most influential factor while others' effects are insignificant. At last, proposed approach is introduced to the analysis of T shaped welded joint test. It turns out simple and convenient in low cycle fatigue assessment since cumbersome modeling of weld local profile becomes not necessary.