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This paper presents a non-destructive capacitance-based technique for rebars detection in reinforced concrete structure. The proposed technique depends on capacitance variation between the two electrodes of a co-planar capacitive sensor while scanning across different concrete sections with and without reinforcement bars. A mathematical model is used to provide meaningful interpretation for the effect of different sensor and concrete parameters on the measured capacitance. The finite element model is built and accompanied by a dedicated experimental setup to confirm theoretical estimations. Simulation and experimental results confirmed a detectable capacitance variation while scanning across the reinforced concrete slab in experimental setup for rebars detection.
In this study, a novel interrelationship between the ventilation rate and the solar chimney design parameters,
EAHE geometrical specifications, pressure drop, and climatic conditions in the hot arid area was presented based
on experimental and numerical comprehensive investigations. This new correlation simplified designing and
optimizing of the passive cooling/heating and ventilation system. Moreover, this correlation was used in a case
study of passive cooling/heating and ventilation of a two-stories residential building in Egypt by TRNSYS simulation.
The indoor operative air temperatures, heating and cooling loads, thermal comfort conditions, energy
consumptions/savings, and CO2 emission savings were calculated and analyzed. Two cases were simulated and
compared with the basic-case. In case 1, the basic-case combined with the solar chimney and EAHE. Case 2 had a
hybrid passive and active ventilation, which included case 1 equipped with electrical fans that continued operating
for 24 h. Finally, an economic study was conducted to calculate the payback period and discount payback
period for the construction of such a system using the local Egyptian market equipment. The basic case results
show that the zonal temperature was more than the ambient temperature yearly, and in summer, the indoor
temperature exceeded the surrounding temperature by 5–6 °C. Using the proposed system in case 1 and case 2
attained a zonal temperature around 5 °C and 9 °C less than the ambient temperature in the summer season,
respectively. However, the total annual electrical energy and CO2 emission savings were 42.9 kWh/m2/year and
4.545 tons/year, respectively, in case 2. Finally, the simple payback period was 5.4 years, and the discount
payback period was 6.8 years.
This study presents an innovative hybrid profiled steel- and fiber-reinforced polymer (FRP) reinforced concrete (HPSFRC) structural system that primarily consists of thin semiclosed T-shaped cold-formed steel sheeting that is externally enclosed with an FRP sheet and filled with concrete. The experimental study was conducted in two interdependent parts: a development study and a validation study. In the development study, six specimens were tested to determine the best interlocking technique between the concrete flange and the other components of the cross section. In addition, two specimens were examined to define the shear strength of the steel-concrete composite profiled system. The validation study presented the flexural behaviors of HPSFRC T-beams with different reinforcement configurations. The test results of the HPSFRC beams were assessed in terms of the behavior of a conventional reinforced concrete T-beam and a composite profiled T-beam. The HPSFRC T-beams achieved a ductility comparable to that of a composite profiled beam but exhibited a higher flexural strength. The flexural behaviors of the HPSFRC beams can be controlled using additional longitudinal reinforcement at the beam tension side. The beam with additional steel bars exhibited ductile behavior with a stable increase in the beam resistance to the applied load; however, the addition of FRP layers enhanced the flexural capacity of the beam and greatly controlled the deformability of the beam after steel yielding, resulting in the lowest measured residual deflection.
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