The search for light weight and efficient structural elements is a continuing process. Reducing the structural weight and improving the load carrying capabilities of steel frames will allow designers to add additional capabilities while reducing cost. Corrugated steel plate shear walls offer several advantages when used to resist both vertical and lateral forces in a building. This paper is devoted to the buckling behavior of steel frames with corrugated steel shear walls. The system consists of two parts, the first one is the envelope steel frame and the second is the infill corrugated steel shear wall. The corrugated steel plates are connected to the surrounding frame beam and columns. The buckling load factor of this system depends on the interaction of many factors including the corrugation configuration of steel plate, the angle of corrugation, the depth of corrugation, the thickness of corrugated plate and the spacing of the fasteners used to attach the corrugated sheets to the steel frame, in addition to the restraint conditions and the external load action. Steel frames with trapezoidal or triangular corrugated steel shear panel were modeled using the finite element software Cosmos/m 2.8 and a linear analysis was performed. In the current study, elastic buckling behavior of steel frames with corrugated shear wall is investigated using finite element approach. The elastic buckling behavior is expressed as normalized load factor which is defined as the ratio between the buckling load of the frame with corrugated plate to the buckling load of the frame without corrugated plate. Parametric analyses were carried out to investigate the effect of spacing between fasteners used to attach the corrugated plate to the envelope frames without or with one, two, and three stiffeners for frames subject to vertical loads only or vertical loads with horizontal loads. The results showed that the spacing between fasteners has significant influence on the elastic buckling behavior of the steel frames with corrugated shear wall.

Glass fiber-reinforced polymer (GFRP) ties are used as structurally and thermally efficient shear connectors for precast concrete sandwich panels (PCSPs) to link the two concrete wythes through a layer of insulation. The excellent mechanical properties and high thermal resistance of these ties have resulted in the growing use of PCSPs in building construction. Several experiments were conducted during the last few years to investigate the optimal distribution of GFRP ties, level of composite action achieved, and minimum required embedment depth for ties. An emerging application for PCSPs is the wall panels for tornado-resistant buildings (e.g. tornado shelters). The lightweight, structural efficiency, thermal and sound insulation, and speed of construction are the main advantages of these panels. This paper introduces the use of large diameter GFRP ties (#5) in 14 in. thick (5-4-5) PCSPs to resist the significantly high wind pressure of tornado zones. The main objective of this research is to experimentally investigate the flexural capacity, horizontal shear capacity, and deflection of tornado-resistant PCSPs using large diameter GFRP ties. A 32 ft long, 4 ft wide, and 14 in. thick panel was fabricated by Concrete Industries Inc., Lincoln, NE using 12#5 GFRP ties and tested at the structural laboratory of the University of Nebraska-Lincoln in Omaha. Testing results indicated that the design of the panel is adequate for resisting the tornado wind pressure calculated according to FEMA 361; and the number, size, and distribution of GFRP ties used in the tested panel are adequate for resisting horizontal shear and achieving the flexural capacity of a fully-composite panel. Panel deflection predicted using truss model was found to be very close to actual panel deflection. The failure mode of the tested panel was the pullout of ties rather than the rupture of ties, which indicated that deeper embedment of ties, is needed to fully utilize the GFRP ties used.

The search for light weight and efficient structural elements is a continuing process. Reducing the structural weight and improving the load carrying capabilities of steel frames will allow designers to add additional capabilities while reducing cost. Corrugated steel plate shear walls offer several advantages when used to resist both vertical and lateral forces in a building. This paper is devoted to the buckling behavior of steel frames with corrugated steel shear walls. The system consists of two parts, the first one is the envelope steel frame and the second is the infill corrugated steel shear wall. The corrugated steel plates are connected to the surrounding frame beam and columns. The buckling load factor of this system depends on the interaction of many factors including the corrugation configuration of steel plate, the angle of corrugation, the depth of corrugation, the thickness of corrugated plate and the spacing of the fasteners used to attach the corrugated sheets to the steel frame, in addition to the restraint conditions and the external load action. Steel frames with trapezoidal or triangular corrugated steel shear panel were modeled using the finite element software Cosmos/m 2.8 and a linear analysis was performed. In the current study, elastic buckling behavior of steel frames with corrugated shear wall is investigated using finite element approach. The elastic buckling behavior is expressed as normalized load factor which is defined as the ratio between the buckling load of the frame with corrugated plate to the buckling load of the frame without corrugated plate. Parametric analyses were carried out to investigate the effect of spacing between fasteners used to attach the corrugated plate to the envelope frames without or with one, two, and three stiffeners for frames subject to vertical loads only or vertical loads with horizontal loads. The results showed that the spacing between fasteners has significant influence on the elastic buckling behavior of the steel frames with corrugated shear wall.

The search for light weight and efficient structural elements is a continuing process. Reducing the structural weight and improving the load carrying capabilities of steel frames will allow designers to add additional capabilities while reducing cost. Corrugated steel plate shear walls offer several advantages when used to resist both vertical and lateral forces in a building. This paper is devoted to the buckling behavior of steel frames with corrugated steel shear walls. The system consists of two parts, the first one is the envelope steel frame and the second is the infill corrugated steel shear wall. The corrugated steel plates are connected to the surrounding frame beam and columns. The buckling load factor of this system depends on the interaction of many factors including the corrugation configuration of steel plate, the angle of corrugation, the depth of corrugation, the thickness of corrugated plate and spacing of the fasteners used to attach the corrugated sheets to the steel frame, in addition to the restraint conditions and the external load action. In the present paper, the effects of corrugation configuration of steel shear wall, and the depth of corrugation on the buckling behavior of such frames subjected to vertical or vertical and horizontal loads were investigated. Steel frames with trapezoidal or triangular corrugated steel shear panel were modeled using the finite element software COSMOS/M 2.8 and a linear analysis was performed.

This paper presents the construction sequences of an innovative precast concrete floor system. The proposed system has a flat soffit similar to cast-in-place flat slabs (no ledges or corbels) and a shallow structural depth compared to conventional precast floor systems. The new system is a total precast floor system that consists of precast concrete columns, precast/prestressed concrete rectangular beams, precast/prestressed concrete hollow-core planks, and cast-in-place composite topping. The system is ideal for six to eight stories buildings with 30 ft x 30 ft bay size, which is typical for hotels and office buildings. Quality, simplicity, and speed of construction are the main advantages of the new system in addition to being aesthetically pleasing. This is mainly due to minimizing cast-in-place operations and eliminating false work and formwork operations as well as the need for shear walls, which are time-consuming and labour intensive. This paper briefly describes the new system, its construction sequence, and preliminary cost analysis.

It is a key economic criterion for multistory residential and office buildings to have a shallow floor that minimizes floor height and saves in the cost of architectural, mechanical, and electrical systems. This paper presents the development of a new precast concrete floor system that eliminates the need for column corbels and beam ledges while being shallow. The proposed system can achieve a span-to-depth ratio of 30 and flat soffit while being consistent with prevailing erection techniques. The proposed system consists of continuous precast columns, prestressed rectangular beams, hollow-core (HC) planks, and cast-in-place composite topping. The paper presents the construction sequence of the new system and focuses on testing HC-beam connections without ledges in a full-scale specimen. Testing results indicate that a 30-cm-deep flat soffit precast floor system has adequate capacity to carry gravity loads (including 488 kg/m2 live load) in a 9.14- 3 9.14-m bay size. Also, testing shows that shear capacity of the proposed HC-beam connections without ledges can be accurately predicted using the shear friction theory.

This paper compares the constructability, cost and schedule of a new shallow flat soffit precast floor system with a typical precast floor system. The new system consists of continuous precast columns without corbels, partially continuous rectangular beams without ledges, partially continuous hollow-core planks (HC), and cast-in-place composite topping. The main criteria in the design of the new system includes: span-to-depth ratio of 30, flat soffit floor system, economy, and consistency with prevailing erection techniques. The new shallow flat soffit precast floor system has a depth and flat soffit comparable to cast in place systems. It has no constructability issues and costs $23.60/ square foot as compared to $21.90/square foot for a typical precast system. Although the new system takes 20% longer erection duration than typical precast system, the flat soffit and shallowness of the proposed system outweighs the cost and duration disadvantages. The continuous beam connections also have the added benefit of eliminating shear walls in moderate wind load conditions. This investigation uses a typical six story hotel or office building with 16 bays 30 ft (9.14 m) x 30 ft (9.14 m) for construction costs and schedule comparisons.

Precast concrete floor systems represent a major component of the cost and weight of precast concrete buildings. Hollow-core (HC) planking is considered the most common precast concrete floor system for residential and commercial buildings because of their economy, light weight, structural capacity, and ease of production and erection. However, the high thermal conductivity of HC planks hinders their use in radiant heated floor and roof applications where thermal insulation is needed. This paper presents the development of a precast/prestressed concrete sandwich floor panel that consists of an internal wythe of insulation and two external wythes of concrete similar to those used in sandwich wall panels. The main difference between the sandwich floor and wall panels is the design of shear connectors between concrete wythes to achieve full composite action under ultimate loads while simultaneously having an adequate creep resistance under ustained loads and acceptable deflection under live loads. Truss-shaped glass fiber-reinforced polymer ties, known as NU ties, were used as shear connectors because of their structural and thermal efficiency. The proposed floor panels have comparable weight and capacity to HC planks while being more thermally efficient and can easily be fabricated in standard casting beds with typical equipment, thus eliminating the high initial investment required for HC production. This paper presents the design, detailing, production, and testing of three 7.9-m-long (26-ft-long), 1.22-m-wide (4-ft-wide), and 200-mm-thick (8-in.-thick) specimens with 50-mm-thick (2-in.-thick) composite topping. The three specimens represent two different panel designs. One specimen has solid concrete ends and was designed for a total superimposed service load of 9.6 kPa (200 psf), whereas two specimens are fully insulated and designed for a total superimposed service load of 4.8 kPa (100 psf). The performance of the three specimens under flexure and shear loadings indicated that the proposed sandwich floor panels can achieve full composite action and have satisfactory structural performance and acceptable deflection characteristics. DOI: 10.1061/(ASCE)SC.1943-5576.0000213. © 2014 American Society of Civil Engineers.

A key economic value for multi-story office buildings, hotels, and similar structures is to have a shallow floor system that reduces the total building height and, consequently, reduces overall building cost. Additionally, minimizing the need for shear walls results in additional economy and flexibility in remodelling. This paper presents the development of a new precast prestressed concrete framing system that achieves both goals for buildings up to six-story tall built in areas of low seismicity. The proposed system consists of precast hollow core slabs, shallow inverted tee beams, multi-story columns, and cast-in-place topping, which are the common components in conventional precast construction. The proposed system eliminates the need for permanent concrete column corbels, and achieves continuity in the inverted tee beam through column block-outs to improve the system’s resistance to lateral and gravity loads. Hollowcore slabs are also made continuous to minimize the need for shear walls in the hollow core direction. An experimental investigation was carried out to verify the theoretical capacities of the system components and to ensure that demand was met for the conditions being considered. Testing was performed using a full-scale specimen representing the area around an interior column. Test results indicated that the system is simple to construct and connection capacities can be adequately predicted using strain compatibility and shear friction theories. The design and construction of an office building in Lincoln, NE was presented as a successful implementation of the new system.

Over the last few decades, the use of precast concrete components have been significantly increasing in building and bridge construction due to their quality, durability, and speed of construction. Precast components need to be fully connected to ensure the integrity, serviceability, and durability of the completed structure. Several proprietary grout-filled sleeves are currently being used to splice reinforcing bars of the adjacent precast components. These sleeves require very tight tolerances in precast production to ensure the alignment of the spliced bars, which usually results in using larger and more costly sleeves than needed. The objective of this paper is to introduce a non-proprietary bar splice sleeve that accommodates current production tolerances in addition to being economical and easy to produce. The design method of the proposed splice sleeve and the analytical investigation conducted using FE analysis are discussed. The experimental investigation conducted using two alternatives of the proposed bar splice sleeve is presented. Eighteen specimens for splicing #8 and #9 bars were tested using different sleeve lengths. Test results indicated that the proposed bar splice sleeve have adequate capacity to fully develop reinforcing bars while being simpler to use and more economical than current proprietary splice sleeve.