Concrete Cracking in Tension Members and Application to Deck Slabs of Bridges

Currently, estimations of the crack width in the deck slab of bridges given by codes of practice are based on either theoretical or empirical approaches considering mainly the monotonic loading behavior. However, cracking in reinforced tensile members is highly influenced by the loading history (including both the loading and unloading processes) because of the irreversible nonlinear behavior of bond and of tensile response of concrete, resulting into residual cracks of non-negligible width. This paper investigates the influence of this phenomenon and presents a physical model describing it. An analytical model is developed and its results are compared to various tests with good agreement. Finally, a simple design formula is derived and recommendations for its application to practical cases are proposed.     

In-group members' perceptions of a social mobility attempt: Effects of boundary permeability and outcome.

This study examined in-group members' impressions of a fellow member who attempted to join a higher power group, along with the interactive effects of the permeability of group boundaries and relative success of this social mobility attempt on impressions. Because groups with less permeable boundaries are typically more cohesive, a group member's relative success in achieving mobility should have meaning for these groups, as opposed to those with more permeable boundaries. Thus, it was predicted that the effect of success versus failure on in-group members' evaluations would be stronger when group boundaries were less permeable. The results showed that a member successful at social mobility was evaluated more positively than one who was unsuccessful, and this difference was larger when boundaries were less permeable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New members and associates of the American Psychological Association.

The Board of Directors announces that the following 2,001 persons were elected to initial membership in the American Psychological Association by the Membership Committee, effective as of July 1, 1987. Of these, 1,630 were elected as Members, and 371 were elected as Associate members. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Zentrische Druckversuche an schlanken UHPC‐Stützen

Axial compression tests on slender columns – unreinforced slender columns: a taboo? – Debate on potential and risk Within the project of the Priority Programme (SPP) 1542 ”Concrete light“, which is funded by the German Research Foundation (DFG), unreinforced UHPC columns with square and rectangular cross‐section were tested under axial compression in the subproject ”Cross sectional adaption for rod‐shaped elements in compression“. The results were compared with test series of other researchers. The focus of the study was on the buckling behavior of columns with different conditions of end support. A hinged and a fixed support have been applied for these experiments. In addition to an analysis of the failure process, the results were compared with the Euler buckling load and the normal stress in consideration of second‐order effects. Concluding, advantages and disadvantages of both approaches are presented, compared, and discussed.     

Earthquake-induced net section fracture in brace connections — experiments and simulations

Results from six tests, finite element simulations and a synthesis of previous test programs on slotted end bracing connections are presented. The main objective of the research is to examine the deformation capacity of these connections, with the ultimate objective of minimizing the requirement for net section reinforcement that is often inconvenient from the perspective of fabrication. The experiments and simulations feature commonly used pipe specimens and end details. The main parameters investigated include the gusset plate thickness, the slot length and introduction of a wrap-around weld that eliminates the reduced section at the edge of the gusset plate. The results indicate that even without reinforcement, the connections offer adequate to excellent deformation capacity if they are provided with the wrap-around weld or if the net section strength is larger than the gross yield strength. This may be achieved in situations where shear lag in the connection is minimal, and where the area reduction due to the slot is small relative to the gross area. Design considerations are presented along with limitations of the study.     

正确处理大学生党员发展工作中数量和质量关系

通过“一个思想、两个重视、三个机制、六个制度”等方面的阐述,辨证看待和正确处理大学生党员发展工作中数量和质量关系,从而保证培养高素质的社会主义事业建设者和接班人。     

"Humanistic" Psychologists.

Having successfully initiated the petition for the establishment of the Division of Humanistic Psychology within APA, I was intrigued by Michael Wertheimer's (see record 1979-22531-001) conclusion that the use of the label humanistic to differentiate this type of psychology from all the rest is unnecessary-particularly since I have arrived at a similar conclusion myself. Outside the APA, many of those who are currently calling themselves "humanistic psychologists" are not really psychologists at all; and the movement seems to be primarily made up of hucksters, charlatans, and perennial therapy shoppers eager to sample the latest far-out techniques--along with a few diehard members of the counterculture left over from the 1960s who are still trying to learn how to be bigger and better hippies. Within APA itself, what is frequently perceived as ideological discrimination is primarily the result of a lack of sufficient intellectual rigor. This in turn has led to the development of a cultic, "us-versus-them" attitude that tends to confuse eccentricity with creativity and to substitute in-group loyalty for the pursuit of excellence. Whatever the situation may have been in the past, humanistic psychology, like Gestalt psychology, may certainly be included in the mainstream of psychological thought today. Henceforth, I shall be happy to think of myself as merely a psychologist, without any identifying ideological label. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Buckling of shear deformable thin-walled members—I. Variational principle and analyticalsolutions

A variational formulation for the buckling analysis of thin-walled members is developed based on the principle of stationary potential energy. The formulation is based on non-orthogonal coordinates and captures shear deformation effects due to bending and warping. It is applicable to members of doubly symmetric cross-sections subject to general axial and transverse forces and naturally incorporates the effect of load position relative to the shear centre. Applying the conditions of neutral stability to the variational expression, the governing differential equations of neutral stability and associated boundary conditions are formulated. The resulting field equations are exactly solved for benchmark cases involving column flexural buckling, column torsional buckling, and lateral-torsional buckling for beams, and the results are compared to closed form solutions based on classical and other modern theories.     

Prediction of the tensile capacity of cold formed angles experiencing shear lag

The present study deals with the shear lag phenomenon in cold formed angles under tension, which are connected on one leg. A new expression for shear lag factor which represents the net section reduction coefficient has been suggested in the present paper. The proposed expression based on the regression analysis of 108 experimental results reported in the literature is validated by experiments involving net section failure in angles under tension. Totally 18 experiments were carried out on single angles fastened with bolts to the gusset plates under tension loaded upto net section rupture mode of failure. The experimental test parameters considered are number of bolts, pitch and shear lag distances and ratio of connected leg length to unconnected leg length. The tensile capacities are evaluated by various specifications such as AS/NZS:4600:2005, NAS:2001, AISC:2005, BS:5950-Part5:1998, IS:800-2007 and the proposed equation. A comparative study of tensile capacities predicted based on various codes and the experiment results is presented in this paper. For the tested range of specimens, both NAS:2001 and AISC:2005 standards over-predicted the capacities for all the specimens. The IS:800-2007 and AS/NZS 4600:2005 predictions are good for the specimens with three bolted connections and unconservative in the case of specimen with two bolts. Both BS:5950-Part-5:1998 and the proposed equation for IS:801 predict good estimate of the tensile capacity of cold formed angle members. The proposed equation for cold formed steel tension members, which is in the same format of IS:800 (2007) (Indian code for Hot rolled steel design), has been demonstrated to be good.     

New members and associates of the American Psychological Association.

The Board of Directors announces that 33,390 persons were elected to initial membership in the American Psychological Association as of January 1, 1975. Of these, 2,277 were elected as Members, and 1,113 as Associate members. This article contains the names of each of these new APA members. (PsycINFO Database Record (c) 2010 APA, all rights reserved)