The experimental behavior of reinforced concrete elements exposed to fire is limited in the literature. Although there are few experimental programs that investigate the behavior of lightweight short ...columns, there is still a lack of formulation that can accurately predict their ultimate load at elevated temperature. Thus, new equations are proposed in this study to predict the compressive strength of the lightweight short column using Gene Expression Programming (GEP) and Artificial neural networks (ANN). A total of 83 data set is used to establish GEP and ANN models where 70% of the data are used for training and 30% of the data are used for validation and testing. The predicting variables are temperature, concrete compressive strength, steel yield strength, and spacing between stirrups. The developed models are compared with the ACI equation for short columns. The results have shown that the GEP and ANN models have a strong potential to predict the compressive strength of the lightweight short column. The predicted compressive strengths of short lightweight columns using the GEP and ANN models are closer to the experimental results than that obtained using the ACI equations.
Drought is one of the most unforgiving natural disasters that could leave severe environmental, economic, and societal impacts. Jordan has witnessed several droughts recently along with recurring ...summer heat waves, which could be a consequence of global warming, and due to the fact that freshwater resources in Jordan are scarce, it is vital to utilize proper modeling and forecasting techniques that will improve the country’s preparedness for possible future droughts. In this study, the annual precipitation data for Amman-Zarqa Basin over the 1980–2016 record were analyzed to identify the occurrence of major droughts in 21 rain stations. Three dimensionless indices which depend solely on precipitation were applied: standardized precipitation index (SPI), standardized precipitation ratio (SPR), and percentage departure from normal (PDN). A comparison was also made among these indices and it was concluded that the SPR and PDN predicted higher numbers of moderate and severe droughts on the expense of extreme droughts compared to the SPI. It was also found that the 1998–1999 year was the driest year in the studied record in which 15 out of 21 stations witnessed extreme droughts. SPI trends were analyzed using the Mann-Kendall test, and it was found that most of the stations experienced negative trends implying increasing droughts over recent years; however, the trends were statistically insignificant for most stations.
It has been argued recently that green growth is the only economic development pathway to secure a sustainable future. The Government of Jordan has launched a National Green Growth Plan aiming to ...facilitate the transition towards green growth in six priority sectors; amongst those is the solid waste management sector. Jordan Vision 2025 has set a 33% reduction target in the solid waste amounts disposed in landfills or dumpsites by 2025. This study examines the development of the municipal solid waste management sector in Jordan from sustainability standpoint and presents potential scenarios to attain Jordan Vision 2025 target and gradually place this sector on a green growth path. The Sustainability Window analysis tool was used to assess the sustainability of this sector over the 2010–2015 period. This tool identifies whether the economic growth maintains the social and environmental wellbeing using strong and weak environmental, social inclusion, and economic indicators. Three scenarios to address Jordan Vision 2025 target were proposed and compared using the Sustainability Window tool: Mechanical biological treatment-anaerobic digestion, mechanical biological treatment-composting, and incineration. It was concluded from the sustainability window analysis of the 2010–2015 data that the total number of jobs in the municipal solid waste management sector is a weak social inclusion indicator compared to the stronger one “jobs per 10,000 tonnes”. Likewise, greenhouse gas (GHG) emissions per tonne is a weak environmental indicator unlike the stronger “net GHG emissions”. It was also inferred from the Sustainability Window analysis that the 2010–2015 Jordanian municipal solid waste sector growth did not fulfill all sustainability criteria. The proposed future scenarios were compared and it was determined that the mechanical biological treatment alternatives fulfill all sustainability criteria regardless of the indicators’ strength, whereas the incineration scenario only satisfies the sustainability criteria using weak environmental indicators. Nonetheless, mechanical biological treatment-composting is the most attractive scenario from an economic perspective owing to the lower GHG mitigation cost of $18.3 per tCO2-eq compared to $35.5/tCO2-eq for the mechanical biological treatment-anaerobic digestion and $161.7/tCO2-eq for incineration.
•The sustainability of the solid waste management sector in Jordan was assessed using the Sustainability Window tool.•The current growth scheme of the Jordanian solid waste management sector is not sustainable.•Mechanical biological treatment plants are sustainable solid waste management alternatives.•The least expensive mitigation measure is the mechanical biological treatment-composting with a cost of $18.3 per tCO2-eq.
This paper experimentally investigate the structural performance of RC beams made with natural aggregate (NA), recycled aggregate concrete (RAC) and reclaimed asphalt pavement concrete (RAP) under ...normal and elevated temperature. The NA was replaced by RAC at two replacement ratios (20% and 40%). Also there was three mixes of 90%RAC-10%RAP, 80%RAC-20%RAP, and 60%RAC-40%RAP. Twelve reinforced concrete beams with a cross-section 150 mm wide, 250 mm high, and a length of 1200 mm were casted and tested. All beams were constructed without stirrups. Six RC beams were tested after exposed 400 °C. Shear strength, ultimate load and mid span deflection were measured. The experimental shear strength was compared to the analytical shear strength calculated using ACI-318-14 and Eurocode-2 formulations. The results showed that temperature has an adverse effect on the shear strength, load capacity, elastic stiffness and deflection of RC beams. Specimens made with RAP and RAC combination exhibited a significant loss in their load carrying capacity under elevated temperature while temperature effect was relatively less remarkable in specimens made with RAC and NA. Increasing RAP percentage in the concrete mix increased the loading carrying capacity of specimens significantly while increasing RAC percentage resulted in a decrease of their load carrying capacity. ACI and EC2 were highly conservative in predicting the shear strength of recycled aggregate.
•Structural performance of RC beams made with recycled aggregate under normal and elevated temperature was investigated.•ACI and EC2 were highly conservative in predicting the shear strength of recycled aggregate.•High RAP and RAC percentage decrease the ultimate capacity at high temperature.
In this article, an experimental program was carried out to investigate the flexural behaviour of RC beams strengthened using side and bottom near-surface mounted (NSM) CFRP strip and rope. Thirteen ...reinforced concrete beams (150x250x1600mm) with flexural deficiency were cast. Different configurations have been used for strengthening RC beams, including side NSM, bottom NSM and both of them. Test results have shown that specimens strengthened with NSM CFRP strips have higher load carrying capacity and higher ultimate deflection than that strengthened with NSM CFRP ropes for the same configuration. FRP debonding, concrete cracks and concrete cover separations are more depicted in specimens strengthened with NSM CFRP ropes than that strengthened with NSM CFRP strips. Using NSM CFRP ropes or strips has increased the elastic stiffness of the strengthened specimens. Flexural strengthening of RC beams using CFRP ropes and strips has increased the load-carrying capacity NSM in a range of (18%-51%) and (30%-80%), respectively, compared to the control specimen. It is also found that beams with bottom strengthening increased the flexural capacity by (25%-32%) compared to RC beams with side strengthening
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