Reliability analysis of moment redistribution in reinforced concrete beams

Design codes allow a limited amount of moment redistribution in continuous reinforced concrete beams and often make use of lower bound values in the procedure for estimating the moment redistribution factors. Here, based on the concept of demand and capacity rotation, and by means of Monte Carlo simulation, a probabilistic model is derived for the evaluation of moment redistribution factors. Results show that in all considered cases, the evaluated mean and nominal values of moment redistribution factor are greater than the values provided by the ACI code. On the other hand, the 5th percentile value of moment redistribution factor could be lower than those specified by the code. Although the reduction of strength limit state reliability index attributable to uncertainty in moment redistribution factors is not large, it is comparable to the reduction in reliability index resulting from increasing the ratio of live to dead load

Bamboo reinforced concrete: a critical review

© 2018, The Author(s). The use of small diameter whole-culm (bars) and/or split bamboo (a.k.a. splints or round strips) has often been proposed as an alternative to relatively expensive reinforcing steel in reinforced concrete. The motivation for such replacement is typically cost—bamboo is readily available in many tropical and sub-tropical locations, whereas steel reinforcement is relatively more expensive—and more recently, the drive to find more sustainable alternatives in the construction industry. This review addresses such ‘bamboo-reinforced concrete’ and assesses its structural and environmental performance as an alternative to steel reinforced concrete. A prototype three bay portal frame, that would not be uncommon in regions of the world where bamboo-reinforced concrete may be considered, is used to illustrate bamboo reinforced concrete design and as a basis for a life cycle assessment of the same. The authors conclude that, although bamboo is a material with extraordinary mechanical properties, its use in bamboo-reinforced concrete is an ill-considered concept, having significant durability, strength and stiffness issues, and does not meet the environmentally friendly credentials often attributed to it

PERANCANGAN BASIS DATA MANAJEMEN KARYAWAN BERBASIS WEB PADA PT. BUMI DARUSSALAM

PERANCANGAN BASIS DATA MANAJEMEN KARYAWAN BERBASIS WEB PADA PT. BUMI DARUSSALAM

Black root rot: a long known but little understood disease

Table S1. Hosts reported to be susceptible to black root rot infection.Table S2. Variation in host susceptibility to black root rot infection by the fungus formally known as Thielaviopsis basicola.Black root rot caused by the pathogen Thielaviopsis basicola has been known since the mid 1800s. The disease is important on many agricultural and ornamental plant species and has been found in at least 31 countries. Since its description, the pathogen has had a complex taxonomic history that has resulted in a confused literature. A recent revision of the Ceratocystidaceae following the advent of DNA sequencing technology has made it possible to resolve this confusion. Importantly, it has also shown that there are two pathogens in the Ceratocystidaceae that cause black root rot. They reside in the newly established genus Berkeleyomyces and are now known as B. basicola and B. rouxiae. This review considers the taxonomic history of the black root rot pathogens, and their global distribution. Prospects relating to the serious diseases that they cause and the likely impact that the era of genomics will have on our understanding of the pathogens are also highlighted.The University of Pretoria, the members of Tree Protection Co‐operative Programme (TPCP), the DST‐NRF Centre of Excellence in Tree Health Biotechnology (CTHB) and the National Research Foundation.https://onlinelibrary.wiley.com/journal/136530592020-06-01hj2019BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Experimental Investigation of Properties of Concrete Containing Recycled Construction Wastes

This research focused on investigating the effects of recycled aggregates on the material properties of concrete and the structural performance of reinforced concrete beams. Two different sources of recycled aggregates, crushed red bricks and demolished concrete, collected from local construction and demolition wastes, were analysed. The pre-wetting method was applied to recycled coarse aggregates aiming to study its effects on concrete specimens. Experimental results assisted by regression analysis revealed that the pre-wetting method could minimize the negative effects caused by recycled aggregate itself on the concrete slump and compressive strength test results. Pre-wetting method was also found improving the dynamic modulus of elasticity for concrete specimens. Adding supplementary cementitious materials was not as effective as the pre-wetting method in enhancing concrete slump, ultrasonic pulse velocity (UPV), strength, or dynamic modulus of elasticity. The reduction of concrete UPV and compressive strength caused by recycled aggregates were more significant in the early curing age. Flexural tests on reinforced concrete beams indicated that although adding recycled concrete aggregates did not significantly change the beam failure load, the ultimate deformation of reinforced concrete beams was reduced by displaying more brittle failure behaviour. It was indicated that the failure mode of beam was changed from flexural to shear, inferring that shear capacity of beam with RCA was reduced. Future research directions were proposed focusing on the durability studies of concrete members containing recycled aggregates especially when the pre-wetting method was applied