Predicted vs Measured Initial Camber in Precast Prestressed Concrete Girders

Prestressing of concrete is the introduction of permanent internal stresses in a structure or system in order to improve its performance. Concrete is strong in compression but weak in tension. The tensile strength of concrete is approximately 10% of the concrete’s compressive strength. Prestressing strands helps counteract this by introducing compressive stress in the area that will experience tensile stress because of the service load. In precast prestressed concrete girders, strands are placed in the bottom flange of the girder. These strands are tensioned to approximately 75% of their ultimate tensile capacity. After placing the concrete and after the required compressive strength has been achieved, the strands are cut and the tension forces transfer from the strands to the concrete. This creates a large compressive stress in the bottom flange. The eccentricity of the pretensioned strands in the prestressed concrete girders creates a bending moment that causes the girder to deflect upward, and this is called camber. This camber is reduced by the downward deflection of the girder due to the girder self-weight. Camber in prestressed concrete girders is effected by several factors, such as the girder’s cross sectional properties, concrete material properties, strand stress, ambient temperature, and relative humidity. Some methods of predicting camber use the initial camber that occurs immediately after cutting the strands to predict the camber at the time of girder erection. There are many sources of errors in predicting camber in a concrete girder including the differences in the actual and the design value of concrete properties and of strand stress. In this study, the difference between the measured and the predicted initial camber will be investigated on six AASHTO Type VI girders. The initial camber was predicted using the simple elastic analysis. The measured initial camber was then compared with the design camber. The difference between using the gross section properties and the transformed section properties to predict camber was quantified. Actual concrete properties including compressive strength, elastic modulus and unit weight were used to assess the current design method. Camber obtained from the actual, measured concrete properties will be called the predicted camber in this study. The effect of using the actual and the design elastic shortening losses on the estimation of the initial camber was also quantified

Social Support Following Pregnancy Loss and its Implications for Women’s Experiences of Posttraumatic Growth

The available literature suggests that social support can contribute to individuals’ positive psychological changes following a traumatic event. However, the effects of the social milieu following pregnancy loss on women’s post-loss adjustment continues to be vastly unexplored. This dissertation explores a gap in the literature surrounding the relationship of interpersonal and intrapersonal social factors on women’s posttraumatic growth (PTG) after miscarriage or stillbirth via three studies. Specifically, the following factors were investigated in relation to PTG: 1) Adult attachment and women’s experiences of dyadic coping; 2) self-disclosure, positive social reactions and deliberate rumination; 3) empathy and prosocial behaviors. Women who had experienced miscarriage or stillbirth were recruited online and completed an online survey that assessed the above mentioned variables as well as demographics and loss context factors. The hypotheses were tested via hierarchical multiple regression, analysis of variance and the PROCESS macro. Overall, the findings across the three studies provide some support for applying PTG theory to women who have experienced pregnancy loss, highlighting the importance of social support in facilitating positive psychological change after the trauma of miscarriage or stillbirth. Specific findings, clinical implications, limitations and recommendations for future research are included in each manuscript

Design of efficient optometric practices: The success factors

Design of efficient optometric practices: The success factor

Impact of Communication on Parents\u27 and First Year College Students\u27 Ratings of Student Academic, Emotional, and Social Adjustment

This study explored the effects of parents\u27 and students\u27 communication patterns on students\u27 social, emotional, and academic adjustment to college. It matched 118 pairs of parents and students (n = 236) and asked them to report their frequency and mode of communication, as well as the first-year students\u27 perceived adjustment to college. The results indicate that on average, parents and students communicate weekly, most often through text messaging. Parents tend to overestimate how well their student has adjusted to college, and asynchronous methods of communication such as texting or e-mail are more frequently positively associated with students\u27 self-reported emotional and social adjustment, whereas real-time communication methods such as phone calls, video chats (Skype), and in-person visits are negatively associated with students\u27 self-reported academic and social adjustment. Models of parent-reported student adjustment indicate that parents perceive their communication efforts as more instrumental to student adjustment than do students

Impact of Communication on Parents\u27 and First Year College Students\u27 Ratings of Student Academic, Emotional, and Social Adjustment

This study explored the effects of parents\u27 and students\u27 communication patterns on students\u27 social, emotional, and academic adjustment to college. It matched 118 pairs of parents and students (n = 236) and asked them to report their frequency and mode of communication, as well as the first-year students\u27 perceived adjustment to college. The results indicate that on average, parents and students communicate weekly, most often through text messaging. Parents tend to overestimate how well their student has adjusted to college, and asynchronous methods of communication such as texting or e-mail are more frequently positively associated with students\u27 self-reported emotional and social adjustment, whereas real-time communication methods such as phone calls, video chats (Skype), and in-person visits are negatively associated with students\u27 self-reported academic and social adjustment. Models of parent-reported student adjustment indicate that parents perceive their communication efforts as more instrumental to student adjustment than do students

The Relationship Between Social Support and Distress Following Perinatal Loss

Perinatal loss can be a traumatic event associated with high levels of distress and potentially PTSD (Berry, 2022). Strong social support is crucial in trauma recovery, though it is often counterproductive following perinatal loss (Meyer, 2016). Recent quantitative research done by Dr. Agata Freedle has shown that lack of adequate, culturally sensitive social support can contribute to elevated levels of PTSD. The specific experiences of perinatally bereaved women have not been captured in this data. Further exploration of this relationship to include the lived experiences of women is needed. The purpose of this study is to qualitatively explore how women experience the relationship between their distress and social support, as well as how women utilize formal and informal social supports to reduce their distress after perinatal loss. Findings will provide insight to both the population that is affected, and also to practitioners in the field who serve this underserved population

An International Comparison of Law Enforcement Stress and Professional Satisfaction

This study was a cross-cultural comparison of stress and coping styles in the U.S. and England. To date, no studies have directly compared police officer stress in the U.S. and England. Police officers were recruited to complete surveys on stress, coping strategies, and job satisfaction. Data collection in England is ongoing, but U.S. results indicate that organizational stress impacted law enforcement officers (LEOs) more than operational stress. Environmental and educational factors also had a significant effect on reported stress. However, marital status was the only factor that influenced which coping strategies LEOs used. This poster will discuss the findings of this study, as well as discuss policy implications relating to stress response strategies