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The purpose of this study was to conduct a meta-analysis that shows the effects of fiber on ultimate compressive ultra-high performance concrete and its tensile strengths. The internet scholarly search engines and ScienceDirect article references were used to illustrate the papers concerning the experimental investigations of mechanical properties of ultra-high strength concrete with and without fiber with clearly, completely and comparative raw data.The normal concrete test results were dismissed from this search. Seven trials were identified based on the adopted inclusion and exclusion criteria above. The meta-analysis based on standardized mean difference was carried out on the basis of a fixed-effects model for the major outcomes of the ultimate compressive and tensile properties of ultra-high performance concrete. A total of 888 test specimens were enrolled in these seven trials. The combined analysis yielded a sign of a significant improvement in ultimate compressive and tensile ultra-high performance concrete strengths with fiber addition of 2% by concrete volume. The summary effect size of ultimate compressive strength was 2.34 while a more improvement in term of tensile strength with effect size of 2.64. By addition fiber of 2% provides a significant benefit in mechanical properties of ultra-high performance concrete.

Pre-stressed members in various structures are gaining popularity among engineers in many parts of the world because pre-stressed strands offer better stability, serviceability, economy, aesthetics, and structural efficiency. The profile of the strand greatly influences the tensile strength of concrete. The force exerted by the strand on the concrete counterbalances internal tensile forces. A construction engineer’s principal goal is to build an excellent strength structure without sacrificing agility and cost-effectiveness. This study’s main objective is to model numerically different pre-stressed concrete slabs to understand and predict the upward deflection (camber) behavior of uniaxial and biaxial pre-stressing of unbonded concrete strands in the static and dynamic behavior and the maximum moments of pre-stressed concrete members by considering previous experimental work as a benchmark for validation. Particular emphasis was placed on the unbonded post-tensioned pre-stressed slab parameters that influence the mid-span upward deflections and internal moments in linear and nonlinear crack analysis. This study also investigated the effect of strand profiles, strand areas, number of strands, strand eccentricities, loading types, and level. It looked into full and partial pre-stressing with uniaxial and biaxial pre-stressing directions. The numerical dynamic characteristics in terms of members’ natural frequency with such parameters were found. This study used a finite element numerical model for the analysis of linear and cracked sections and concluded that the upward deflection (camber) of uniaxial and biaxial one-way and two-way partially unbounded pre-stressed concrete slabs is affected by the strand’s profile, area, and number and eccentricity; the loading type and value; and the pre-stressing level in static and dynamic analyses.

The effect of prestress force value on the dynamic characteristic members dynamic characteristics been excessively argued among researchers till now. This study aims to perform a statistical method based on a meta-analysis investigating the influence of prestressing force on the first mode shape natural frequency of a prestressed reinforced concrete member and the related prestressing loss. The prior trials extracted from ScienceDirect, Scopus, Clarivate, and Research Gate electronic databases were used. The inclusion criteria encompass previous trials concerning experimental investigations of vibration frequencies as a function of prestressing force level with data capable of covert statistically to more meaningful information. Both analytical and numerical trials were excluded in this study. Twelve trials were matched with the objective of this review paper and satisfied the inclusion and exclusion criteria. A fixed-effects model type of meta-analysis was carried out based on the standardized mean difference. The present study shows a medium role for the prestress force in effecting the first vibration natural frequency mode. The total effect size is 0.93 standard deviations with 0.562-1.280 confident interval. The synthesized statistical analysis proves the efficiency of the meta-analysis method in predicting the influence of prestressing force on first eigenvalue frequency.

Road accidents have been identified as one of the main causes of death and have a significant effect on public health challenges, economic growth and development. The Iraqi transport infrastructure has suffered from the effects of war, carelessness, and lack of investment. As a result, road traffic accidents have increased, and the current efforts to address road safety are minimal in comparison to the growing level of citizen suffering. The objective of this study was to provincially analyze traffic accidents in Iraq using data from 2010 to 2020 to shed light on the current situation. Three key conclusions were made from the results: first, people aged 35 years and under was the age group recorded in the most traffic accidents; second, Al-Najaf province recorded the highest rate of traffic accidents; and third, COVID-19 lockdown in Iraq caused a 28.5 % decline in traffic accidents while fatality and injury rates fell by 28 % and 18.4 % respectively, when comparing with the data of the same period in 2019.