Numerical parametric study on ultimate load and ductility of concrete encased equal-leg angle steel composite columns

Steel-concrete composite high bridge pier has been applied increasingly in China and around the world. Most applied steel type in the composite piers are H-shaped steel and steel pipe, while seldom research or practice is associated with angle steel. This paper conducted parametric study on the composite column with equal-leg angle steel and aimed to investigate the ultimate load and displacement ductility of the composite columns with different parameters. The parameters include the type of shear connector (stud and perfobond connectors), the type of structural steel (H-shaped steel and angle steel), steel-plate hooping ratio, shear-span ratio, and axial compression ratio. Finite element analysis was conducted for each specimen, which incorporated the concrete confinement effect, as well as the inelastic behavior of concrete, structural steel, and longitudinal and transverse steel bars. The equal-leg angle steel composite column was found to have slightly higher strength and displacement ductility than H-shaped steel composite column. The increase of steel-plate hooping result in larger strength and displacement ductility for the composite column, and the increase of shear-span ratio and axial compression ratio decrease the displacement ductility. Research results suggest stud and perfobond shear connectors should be applied as axial compression ratio being larger than 0.2 and 0.3, respectively. This paper provides reference for research and engineering practice of the concrete encased angle steel composite columns and bridge piers.Accepted Author ManuscriptSteel & Composite Structure

Role of Surface Roughness in Surface Energy Calculation of Aggregate Minerals

Surface energy is a key material property and can work as a crucial parameter in various mechanical models to predict the moisture sensitivity and fatigue damage of asphalt mixtures. The calculated surface energy values of the aggregate minerals strongly depend on their surface roughness. Therefore, it is very relevant for accurate calculation of surface energy to study the relationship between roughness and surface energy. This study aims to investigate the relationship between surface roughness and surface energy of aggregate minerals. Two minerals—quartz and calcite—were used for this study. The surfaces of the mineral specimens were treated to achieve four levels of roughness. Their surface roughness was described by three roughness parameters. Based on the sessile drop method, an optical tensiometer with a 3D topography module was employed to measure the contact angle and the surface energy of the minerals with different roughness. The influences of surface roughness on the contact angle and the surface energy were then analyzed. The results showed that the contact angle for both quartz and calcite decreases with the increasing surface roughness when it is less than 90° and increases when it is greater than 90°. The Wenzel equation can remove the effect of surface roughness on the contact angles of the minerals. The surface energy of quartz and calcite in the presence of roughness at the microscale would be underestimated when using the measured (apparent) contact angle. The corrected surface energy based on the Wenzel equation must be applied to represent the real surface energy of the minerals.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Pavement Engineerin

Assessment of Flexural Behavior of Pultruded GFRP Laminates for Bridge Deck Applications

In this study, flexural behaviors of the pultruded composite laminate were evaluated through experiments and theoretical analysis. Three-point flexural tests were performed for pultruded specimens. The typical failure mode for the longitudinal flexural specimens was local crush on the top surface accompanied with local cracks on the bottom surface at midspan. For the transverse tests, the specimens presented a failure pattern with local cracks initiated and propagated at both the top and bottom sides at the midspan. Theoretical analysis, based on micromechanics and macromechanics, was performed to predict flexural deformation and stress distribution of the pultruded laminate beam. Based on the continuum damage model proposed by the authors, this paper mainly investigates the flexural behavior and failure pattern of pultruded lamination. The theoretical and finite element results agreed well with the test results. The results can provide a reference for the design of the structural pultruded modular systems.Steel & Composite Structure

Sustainable Passive Design for Building Performance of Healthy Built Environment in the Lingnan Area

Having a healthy built environment becomes increasingly important, especially under the effects of COVID-19. This paper intends to combine sustainable goals based on climate change with passive design principles to achieve a healthy built environment regarding the building performance of residential buildings. The Yuedao Residential Community in the Lingnan area was taken as an example for the research. Based on relevant standards of healthy buildings, the thermal, light, and acoustic environment requirements were determined. The methods of building performance simulation and on-site measurement were used to quantify the research object environments. Then, the outcomes were obtained based on these standards. As observed, the thermal environment’s adaptive thermal comfort level was level III. It was hot indoors, but the light and acoustic environments met the requirements. Building designs based on a built environment optimized by external shading systems aim to solve problems through building performance simulation and qualitative analysis. After optimization, the thermal environment improved. According to the literature review, this research focused on a healthy built environment with a sustainable passive design in terms of building performance. A research workflow was established that could be used for more practical research, with abundant research methods. The problems were solved to varying degrees, and the Lingnan architectural culture was preserved. Moreover, this research filled the gap in interactive research on healthy built environments with sustainable passive design regarding building performanceGeneral Suppor

The hydro-mechanical interaction in novel polyurethane-bound pervious pavement by considering the saturation states in unbound granular base course

The pore-water pressure generated by intermittent dynamic vehicle loading under various saturation states is recognized as a critical factor influencing the behaviour of permeable pavement structures, especially the behaviour of UGB layer. However, the underlying mechanisms of hydro-mechanical interaction in the UGB layer and the influence on the pavement structure are still unclear. This study aims to characterize the changes in dynamic response in permeable pavement structures under various saturation conditions by considering the hydro-mechanical interaction within the UGB layer. To achieve this objective, a full-scale test track with a PUPM wearing course was constructed. Pressures and water distribution were characterized by embedded sensors within different layers of the test track when subjected to the accelerating pavement test. Based on the coupled SAME model, the water distribution and the dynamic response of UGB in the rainfall events were both characterised and solved by FEM. The results predicted by the proposed SAME model correspond to the field measurements, and the influence of the water content on the resilient modulus distribution within the UGB layer was then estimated. Based on the predictions for the stress state of the UGB layer, the sensitivity analysis was also proposed.Accepted Author ManuscriptPavement Engineerin

Risk Factors of Posttraumatic Stress Disorder among Survivors after the 512 Wenchuan Earthquake in China

This study investigated the psychological reactions of survivors of the 512 Wenchuan earthquake in China and the risk factors associated with those reactions. The Impact of Event Scale-Revised (IES-R), Type D Scale-14 (DS14), a self-developed trauma experience questionniare, and a demographic questionnaire were administered to 956 earthquake survivors (389 males and 567 females) in Mianzhu, one of the cities most affected by the earthquake. The results showed that postraumatic stress disorder (PTSD) symptoms affected 84.8% of survivors one to two months after the earthquake. Significant risk factors associated with PTSD symptoms included: (1) being female; (2) older age; (3) higher exposure to traumatic events during the earthquake; and (4) negative affect in Type-D personality

Factor structure of the Children's Revised Impact of Event Scale among children and adolescents who survived the 2008 Sichuan earthquake in China

To evaluate the psychometric properties of the Chinese version of Children's Revised Impact of Event Scale (CRIES) and its applicability among Chinese children and adolescents, a study was conducted on two samples, the first, 1 month after the 2008 Sichuan earthquake, the second, 7 months after the earthquake. High levels of posttraumatic stress symptoms were found among both groups of children. The results also showed a decline of intrusion and arousal symptoms in accordance with the different periods of time elapsed since the earthquake; however, no difference was found in the avoidance symptoms between the two samples. Both the subscales and the CRIES total showed moderate to good reliability. Confirmatory factor analysis (CFA) of CRIES supported the presumed three inter-correlated factors model. However, the results of the second sample (with more than 6 months elapsed subsequent to the earthquake) are more likely to support this model than those of the first sample. This study generally justifies the use of CRIES as a screening instrument for probable PTSD victims among children and adolescents exposed to horrible natural disasters in China. Limitations of the present study and directions for future research are also discussed

Structure of the Children's Revised Impact of Event Scale (CRIES) with Children and Adolescents Exposed to Debris Flood

Aim: PTSD symptoms were pervasive among children and adolescents after experiencing or exposure to traumatic events. Screening and diagnosis of PTSD symptoms is crucial in trauma-related research and practice. The 13-item Children's Revised Impact of Event Scale (CRIES) has been demonstrated to be a valid and reliable tool to achieve this goal. This study was designed to examine the psychometric properties of the 13-item CRIES in a sample of Chinese debris flood victims

Cross-informant agreement between parent-reported and adolescent self-reported problems in 25 societies

We used population sample data from 25 societies to answer the following questions: (a) How consistently across societies do adolescents report more problems than their parents report about them? (b) Do levels of parent-adolescent agreement vary among societies for different kinds of problems? (c) How well do parents and adolescents in different societies agree on problem item ratings? (d) How much do parent-adolescent dyads within each society vary in agreement on item ratings? (e) How well do parent-adolescent dyads within each society agree on the adolescent's deviance status? We used five methods to test cross-informant agreement for ratings obtained from 27,861 adolescents ages 11 to 18 and their parents. Youth Self-Report (YSR) mean scores were significantly higher than Child Behavior Checklist (CBCL) mean scores for all problem scales in almost all societies, but the magnitude of the YSR-CBCL discrepancy varied across societies. Cross-informant correlations for problem scale scores varied more across societies than across types of problems. Across societies, parents and adolescents tended to rate the same items as low, medium, or high, but within-dyad parent-adolescent item agreement varied widely in every society. In all societies, both parental noncorroboration of self-reported deviance and adolescent noncorroboration of parent-reported deviance were common. Results indicated many multicultural consistencies but also some important differences in parent-adolescent cross-informant agreement. Our findings provide valuable normative baselines against which to compare multicultural findings for clinical samples

International Epidemiology of Child and Adolescent Psychopathology II: Integration and Applications of Dimensional Findings From 44 Societies

Objective: To build on Achenbach, Rescorla, and Ivanova (2012) by (a) reporting new international findings for parent, teacher, and self-ratings on the Child Behavior Checklist, Youth Self-Report, and Teacher's Report Form; (b) testing the fit of syndrome models to new data from 17 societies, including previously underrepresented regions; (c) testing effects of society gender, and age in 44 societies by integrating new and previous data; (d) testing cross-society correlations between mean item ratings; (e) describing the construction of multisociety norms; (f) illustrating clinical applications. Method: Confirmatory factor analyses (CFAs) of parent, teacher, and self-ratings, performed separately for each society; tests of societal, gender, and age effects on dimensional syndrome scales, DSM-oriented scales, Internalizing, Externalizing, and Total Problems scales; tests of agreement between low, medium, and high ratings of problem items across societies. Results: CFAs supported the tested syndrome models in all societies according to the primary fit index (Root Mean Square Error of Approximation [RMSEA]), but less consistently according to other indices; effect sizes were small-to-medium for societal differences in scale scores, but very small for gender, age, and interactions with society; items received similarly low, medium, or high ratings in different societies; problem scores from 44 societies fit three sets of multisociety norms. Conclusions: Statistically derived syndrome models fit parent, teacher, and self-ratings when tested individually in all 44 societies according to RMSEAs (but less consistently according to other indices). Small to medium differences in scale scores among societies supported the use of low-, medium-, and high-scoring norms in clinical assessment of individual children. J. Am. Acad. Child Aclolesc. Psychiatry; 2012; 51(12):1273-1283