Aims and Scope

The Open Civil Engineering Journal is an Open Access online journal which publishes research, reviews/mini-reviews, letter articles and guest edited single topic issues in all areas of civil engineering.


The Open Civil Engineering Journal, a peer-reviewed journal, is an important and reliable source of current information on developments in civil engineering. The topics covered in the journal include (but not limited to) concrete structures, construction materials, structural mechanics, soil mechanics, foundation engineering, offshore geotechnics, water resources, hydraulics, horology, coastal engineering, river engineering, ocean modeling, fluid-solid-structure interactions, offshore engineering, marine structures, constructional management and other civil engineering relevant areas.


Recent Articles

Minimum Depth-Span Ratio of Beams in order to Control Maximum Permissible Deflection

Mereen H. Fahmi Rasheed, Ayad Zeki Saber Agha

Background:

ACI code and other building codes and standards include the provisions for deflection control and depth-span limitations, also including the maximum permissible deflection for specified concrete and steel reinforcement strength. In this study, the effects of applied load intensity, steel reinforcement index amount as a ratio to the balancing reinforcement index (ρ/ρb), concrete strength (fc' ) and beam width on the depth-span ratio of the beam with different types (simply supported, fixed ended, propped and cantilever) were investigated.

Objective:

This study aimed to study the effect of applied load intensity, steel reinforcement index amount as a ratio to the balancing reinforcement index (ρ/ρb), concrete strength (fc' ) and beam width on the depth-span ratio of the beam of different types (simply supported, fixed ended, propped and cantilever).

Methods:

This study theoretically investigates the effect of applied load intensity, steel reinforcement index amount as a ratio to the balancing reinforcement index (ρ/ρb), concrete strength (fc' ) and beam width on the depth-span ratio of the beam of different types (simply supported, fixed ended, propped and cantilever).

Results:

The results show that the effect of the ratio (ρ/ρb) is small on the depth-span ratio, and the required depth of the beam increased with increasing the applied distributed load value and decreased with increasing the concrete strength for all beam types.

Discussion:

Deflection of slabs and beams can be controlled by the addition of steel reinforcement bars or using pre-stressing concrete, loading type and value, material properties (E), section properties (I), and the type of the member. The results showed that the effect of the ratio (ρ/ρb) was small on the depth-span ratio, and the required depth of the beam increased with increasing the applied distributed load value and decreased with increasing the concrete strength for all beam types.

Conclusion:

- A modification of ACI Code span-depth ratio is suggested to include the effect of tension reinforcement area which is represented by the reinforcement indices ratio (ρ/ρb), applied distributed load (w), concrete compressive strength (fc' ) and cross section width (b) in order to control the maximum deflection of the beam within the ACI limit of the maximum permitted deflection.

- The value of span-depth ratio (N = L / h) is determined for four types of beam (simply supported, fixed ended, propped and cantilever) for concrete strengths (fc' = 21, 28, 35, 42, 63 & 84 MPa), applied distributed load (w = 14.6, 29.2, 43.8 & 58.4 kN/m), cross width (b = 150, 200, 250 & 300 mm) and (ρ/ρb = 0, 0.5 & 1) in addition to (ρt /ρb & ρmax /ρb).

- The effect of the reinforced indicia ratio (ρ/ρb) is small on the span-depth ratio (N = L / h) for all values of applied load and concrete compressive strength.

- The span-depth ratio (N = L / h) decreased with increasing the applied load, or in other words, the required depth increased with increasing the applied load for all values of concrete strength and beam width.

- The span-depth ratio (N = L / h) increased with increasing the concrete strength (fc' ), i.e. the required depth decreased with increasing concrete strength for all values of applied loads and beam width.

- The same behavior and conclusions are obtained for all beam types (simply supported, fixed ended, propped and cantilever).


December 31, 2020
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Editor's Choice

Development of Ductile Truss System Using Double Small Buckling-Restrained Braces: Analytical Study

Hidajat Sugihardjo, Yudha Lesmana, Dwi Prasetya

Introdution:

This paper proposed a Small Buckling-Restrained Brace (SBRB) for the ductile truss moment frames and is called here as the Double Braced Truss Moment Frames (DB-TMF). The braces are located at the edge of the truss girder and are only placed around the building perimeter. The braces work in pair as a weak element (structural fuses) and is expected to effectively absorb the seismic energy. The proposed DB-TMF system is an extended development of the Knee Braced Truss Moment Frames (KB-TMF). The DB-TMF system is expected to carry the whole seismic loads, while the rest of the frame is designed to carry only the gravity loads.

Methods:

To study the performance of the proposed DB-TMF system, non-linear finite element analysis was carried out using the DRAIN-2DX package. From the analysis with various time history records, it was found that the drift ratio of the DB-TMF system is lower than the allowed story drift. The roof-top displacement shows an asymptotic behavior. The shape of the hysteresis curve tends to have a pinching shape. However, the cumulative ductility of the proposed system satisfies the requirements as a hysteretic structure. In the event of an earthquake, only the SBRB and the chords adjacent to the column element are damaged while the rest of the structural elements remain elastic which is expected.

Results and Conclusion:

Based on the performance evaluation of the DB-TMF system, the DB-TMF system is suitable for moderate seismic region and has smaller dimension steel sections compared to the KB-TMF system.


February 28, 2019
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