Floor Beams Research Articles

Metode Pelaksanaan Pekerjaan Struktur Balok dan Pelat Lantai 2 Pembangunan Gelanggang Generasi Muda Majalengka

Beams and Floor Plates are a very important construction structure in a building. In carrying out work on floor slabs and beams, a method is needed to complete the work in the field. Especially when facing obstacles caused by field conditions that do not match previous expectations. For this reason, applying construction implementation methods that are appropriate to field conditions will be very helpful in the process of completing construction projects. Research on the construction method for the beam and floor slab construction was carried out at the Majalengka Young Generation Center construction. The casting method for the beams and floor slabs is conventional using ready mix concrete with a slump test value of 12 ± 2. From the results of the research on the construction implementation method for the Majalengka Young Generation Arena, it was found that: beam and floor plate work includes, preparatory work includes measuring work, scaffolding installation and formwork installation, then there is reinforcement/reinforcing work, namely steel fabrication in the project area, then there is work Casting the beams and floor plates using a tower crane. Next, maintenance work is carried out on the concrete mixture during the drying process, namely by watering according to regulations.

Combined Acoustic Emission and Ultrasonic Measurements in Cross Laminated Timber-Steel Composite Beam

Combined acoustic emission and ultrasonic measurements were carried out before and during a four-point bending test on a composite floor beam made of cross-laminated timber with length of 11.6 m, width of 1.5 m, and thickness of 0.28 m. One key aspect of the composite design is the formation of the shear-resistant connection between the panel and steel girder. For the measurements a 16-channel system with combined acoustic emission and transmission measurements was used. The signals were digitized with a very high frequency of 10 MHz with amplitude resolution of 16 bits. To monitor acoustic emission activity a network of 16 AE sensors were attached to the surface of the specimen in the central part of the specimen where the highest deflection and load were expected. For this purpose, broadband AE sensors with measurement frequency of up to 200 kHz were used. The ultimate failure of the specimen occurred at a maximum test load of approximately 200 kN. The deflection at this force was about 200 mm. During the tests which lasted about 50 minutes approximately 8,500 AE events were detected. More than 2,600 events were recorded by at least six channels which makes them well suited for three-dimensional localization. Because of the inhomogeneous cross-laminated timber conventional localization using an unique velocity model are not possible. Therefore, a velocity model was experimentally determined by measure the velocity of the elastic waves in all directions. The greatest value was measured in the longitudinal direction along the beam axis. The average value is approximately 4000 m/s. While in the transverse direction the velocity drops down to approximately 2800 m/s. The lowest value was measured in thickness direction of about 1800 m/s.

ANALYSIS OF LABOR PRODUCTIVITY OF BEAM AND FLOOR PLATE WORK WITH WORK SAMPLING METHOD

Productivity is a crucial parameter in achieving project objectives. This research aims to obtain the value of labor productivity on the beam structure and floor plate in home construction using the work sampling method and analyze the comparison of the labor coefficient to the Analysis of Unit Price of Work (AHSP) in 2022. Experimental quantitative research describes this approach, utilizing information gathered through documentation, questionnaires, and participant observation. Data analysis in this research includes Data Uniformity Analysis, Data Sufficiency Analysis, Labor Utilization Rate (LUR), and Spearman Correlation. The findings revealed that the beam concreting job in home construction achieved a labor productivity rate (LUR) of 61.61% and 84.417 kg/person. In the floor plate concreting work, labor productivity reached 98.787 kg/person with a LUR value of 54.10%. Meanwhile, in formwork work, labor productivity reached 3.577 m/person with a LUR value of 53.37%, and in casting work, labor productivity reached 1.287 m/hour with a LUR value of 53.37%. Correlation analysis shows a positive relationship between Labor Utilization Rate and labor coefficient in concreting and formwork works. This indicates that the more efficient the labor, the higher the productivity in carrying out these activities, and the smaller the coefficient value obtained

Investigation of Effective Notch Stress at the Root of the Rib-to-Deck Weld in an OSD Box Girder Bridge Considering the Wheel Load Position

AbstractFatigue cracks have been reported in orthotropic steel deck bridges under severe traffic conditions in Japan, particularly root-deck and bead cracks, which initiate from the root of the rib-to-deck weld. The local stress directly influencing crack initiation was investigated using a finite element model based on a section of an actual bridge with a high incidence of cracks. The analysis focused on the weld root at the floor beam intersection and the span center of the bridge section. The model was subjected to loading in the transverse and longitudinal direction of the bridge combined with various wheel load configurations. The effect on the local stress properties was analyzed using the effective notch stress approach. A load position slightly off-center of the U-rib resulted in peak stress at the study locations. Its principal stress direction angle around the notch suggests a root-deck type of crack initiation. Testing several pavement stiffnesses revealed that using an SFRC pavement resulted in a 76%–84% reduction of peak effective notch stress compared to asphalt pavement. Furthermore, varying weld configurations demonstrated that lowering the weld penetration rate could alter the local stress position, influencing the crack initiation direction.

Distribution and propagation of stress and strain in cube honeycombs as trabecular bone substitutes: Finite element model analysis

For designing trabecular (Tb) bone substitutes suffering from osteoporosis, finite element model (FEM) simulations were conducted on honeycombs (HCs) of 8 × 8 × 1 (2D) and 8 × 8 × 8 (3D) assemblies of cube cellular units consisting of 0.9 mm long Nylon® 66 (PA, Young's modulus E: 2.83 GPa) and polyethylene (PE, E: 1.1 GPa) right square prisms. Osteoporotic damage to the Tb bone was simulated by removing the inner vertical struts (pillars; the number of removed pillars: Δn ≤ 300) and by thinning the strut (thickness, d: 0.4–0.1 mm), while the six facade lattices were kept flawless. Uniform and uniaxial compressive loads on the HCs induced elastic deformation of the struts. The pillars held almost all the load, while the horizontal struts (beams) shared little. E for PA 3D HCs of all d smoothly decreased with Δn. PA 3D HCs of 0.2 mm struts deserved to be the substitutes for Tb bone, while PE 3D HCs of 0.05 mm struts were only for the Tb bone of the poorest bone quality. For the PA 3D HCs, the maximum von Mises stress (σM) first rapidly increased with Δn and showed a break at Δñ50, then gradually approached the yield stress of PA (50 MPa). Moreover, small portions of the stress were transferred from the façade pillars to the adjacent inner beams, especially those near the lost-pillar sites, denoted as X defects. The floor beams of thinner struts associated with the X-defects were lifted, and similar lifting effects in smaller amounts were propagated to the other floors. The 3DHCs of the thicker struts showed no such flexural deformations. The concept of force percolation through the remaining struts was proposed to interpret those mechanical behaviors of the HCs.

Study on the Damage Evolution and Failure Mechanism of Floor Strata under Coupled Static-Dynamic Loading Disturbance

In the field test, we found that the failure depth of the goaf floor strata tends to be further because the periodic breaking and caving of the immediate roof, upper roof, and roof key stratum has dynamic stress disturbance effects on the floor. To further analyze its formation mechanism, this paper studies the damage evolution and fracture mechanism of goaf floor rock under the coupled static-dynamic loading disturbance caused by roof caving, based on the stress distribution state, the damage evolution equation of coal measure rock, the damage constitutive model, and the fracture criterion of floor rock. The main conclusions are listed as follows: 1. Based on the mining floor stress distribution, the floor beam model establishes the response mechanism of floor rock stress distribution. Also, the equation of stress distribution at any position in floor strata under mining dynamic load is given. 2. Combining the advantages of Bingham and the Generalized-Boydin model, the B-G damage constitutive model is established, which can describe the constitutive characteristics of coal measure rock under the coupled static-dynamic loading disturbance well. Furthermore, the variation law of parameters changing with strain rate is analyzed. 3. According to the twin-shear unified strength yield theory and the B-G damage constitutive model, coal measure rock’s twin-shear unified strength damage fracture criterion is established. Finally, the stress distribution expression of floor strata under concentrated and uniform dynamic loads is introduced, and the fracture criterion of goaf floor strata under a coupled static-dynamic loading disturbance is proposed.

Progressive Collapse and Post Impact Damage Assessment in a Regular Beam-Slab Building & Flat-Slab Building on the Intermediate Floor

Progressive collapse, where a localized member failure causes widespread structural collapse, has become a critical concern nowadays, due to its potential to cause significant financial losses and loss of human life. Triggers include natural disasters like earthquakes and floods, as well as accidents, attacks and explosions. Reinforced concrete flat slab structures, which are eminent for their architectural flexibility and have larger spans, are particularly susceptible to disproportionate collapse, due to the lack of floor beams, which can redistribute loads after a column failure, unlike moment frame buildings. This research examines how multi-story reinforced concrete flat slab buildings behave, under prescribed gravity load combinations, compared to conventional framed buildings. The effects of removing columns at specified locations from an intermediate floor of the multistorey building are also examined. However, this investigation covers both the column removal approaches to check a possibility of disproportionate collapse which are; static removal and dynamic instantaneous removal. Furthermore, the research also assesses the efficacy of perimeter beams, in minimising the risk of gradual collapse in flat slab structures, by scrutinising their ability to reduce joint displacement, chord rotation, and demand capacity ratio. ETABS v18 was used to analyze all the 18 models. The findings revealed that buildings are more prone to progressive collapse when corner columns are removed, as opposed to edge and interior columns, due to higher Demand-Capacity Ratios (DCR) and joint displacement. In comparison to dynamic analysis, the static evaluation exhibited greater DCR values and vertical joint displacement. Furthermore, since they have a more efficient load redistribution mechanism, traditional framed structures performed better than flat slab models. The simulations additionally indicated that, adding edge perimeter beams, substantially lowered the possibility of progressive collapse in flat slab structures. Moreover, the tested flat slab building models, with and without perimeter beams showed no indications of progressive collapse, when specified columns were removed from the intermediate floors, since the DCR values of the crucial columns stayed within the permissible range of 2.0. In conclusion, structures built in compliance with IS 1893:2016 code and designed to withstand seismic loads demonstrate stronger resistance against significant damage, brought about by column failures.

Bending test of long-span ultra-shallow floor beam (USFB) with two lightweight concretes

This paper presents the bending behaviour of a partially encased ultra-shallow floor beam (USFB) with two types of lightweight concrete. The beam was fabricated by welding two asymmetric Tees together along the web to create a beam with multiple circular openings that act as ‘plug shear connectors’ with the concrete encasement. The bending resistance of the plug-shear connection system was obtained by testing a composite USFB for a beam span of 7.2 m, half of the span being made with a lightweight concrete slab and the other half span with an ultra-lightweight concrete slab. Analysis of the four-point bending tests was carried out to determine the increase in bending resistance due to composite action and the contribution of the longitudinal shear connection due to the concrete plug passing through the web openings combined with additional tie bars. Calculations of the properties of the USFB with the two types of lightweight concrete were made according to SCI documentation and Eurocode 4. It was observed that the deflections were predicted accurately by the elastic properties and that the failure mode was by concrete crushing before the plastic bending resistance of the composite section had been developed. It was also shown that the cracked section properties should be used for the deflection analysis.

Shear Lag Effect and Its Additional Deflection Contribution of Composite Beam Bridges

The composite beam structure is widely used in the engineering field because it benefits from the advantages of two materials, presenting outstanding advantages for construction purposes. However, at present, there are issues with the analysis and solution of the composite beam structure, such as the difficulty in developing a suitable analytical theory and the low degree of refinement achieved by simulation analysis. To accurately grasp the mechanical behavior of the composite beam structure and achieve its refined analysis, this paper proposes a refined spatial grid element analysis method that can simultaneously obtain the internal forces, displacements, and stresses of various parts of a composite beam. Based on the above new method, the effects of geometrical structural factors such as wide-span ratio, high-span ratio, and web thickness with respect to the shear lag effect are analyzed. The distribution law of the shear lag coefficient and its additional deflection are analyzed. The results demonstrate that using this analysis method to calculate and analyze steel-concrete duplex type composite beams can directly obtain the internal forces and displacements of the joints of the composite beam roof, floor, and web. The spatial grid element analysis method provides both the theoretical and practical means to achieve both the overall and local refinement analysis of the composite beam structure.

Vibration response of ultra-shallow floor beam (USFB) composite floors

This paper examines the vibration response of the steel-concrete composite Ultra Shallow Floor Beam (USFB®) flooring system which incorporates asymmetric steel perforated beams to accommodate the concrete floor slab within the depth of the flanges while allowing reinforcement and/or service ducts to pass through the web openings. This is a lightweight flooring system that can accommodate long spans, thus becoming susceptible to floor vibrations due to external resonant dynamic loads. To investigate the influence of slab thickness and boundary conditions on the natural frequencies of the USFB flooring system, parametric studies are conducted using a finite element model and five floor spans. The model was first validated against an experimental test conducted by the authors. Emphasis is placed on the fundamental frequency to predict the possibility of resonance of this complex flooring system with typical human-induced dynamic loads in building structures. To further facilitate the practical numerical modelling and vibration analysis of buildings with USFB floors in standard commercial structural software, an analytical method of deriving equivalent isotropic plate properties is developed and its accuracy is numerically verified vis-à-vis with detailed ABAQUS models.

A new cross-section layout method and geometrical parameter optimization for floor beams of rack car body considering modal factors

A new cross-section layout method and geometrical parameter optimization for floor beams of rack car body considering modal factors

Correction: Study on vibration performance and comfort of glulam beam and deck floor

Correction: Study on vibration performance and comfort of glulam beam and deck floor

Study on vibration performance and comfort of glulam beam and deck floor

Study on vibration performance and comfort of glulam beam and deck floor

Composite Delta Beam for Slim Floor Construction

Abstract: The structural behaviour of the composite Flush Beam for slim floor as a whole has been investigated. The deformation behaviour of the structural members Steel beams with trapezoidal cross-sections and specially punched webs were developed as composite beams in slim floors. The estimation of the flexural stiffness and bending capacity of composite slim beams is rather complicated, because the influence of many factors should be taken into account. These factors include variable section dimensions, Profile of the beam, stiffness of the beam and interaction between steel and concrete. In this paper, analytical investigations have been conducted to investigate the deflection behaviour of Flush beam specimens under monotonic loading. A design procedure is developed for composite slim floor Flush beams based on cross-sectional analysis and the flexural properties of the slim floor beams are evaluated. From the analytical investigation it was found that the deflection of delta beam is 48% less than the conventional I-beam More over the stiffness of the Delta beam is 49.8% higher than the I-beam

A CFRP Passenger Floor Stanchion Underwent Dynamic Buckling Structural Testing

AbstractThe work focuses on the study of the structural behaviour of a composite floor beam in the cargo area of a commercial aircraft subjected to static and dynamic loads (typical of hard or crash landing). Experimental tests have been performed in the laboratories of the Dept. of Industrial Engineering (UniNA) jointly with the development of numerical models suitable to correctly simulate the phenomenon through the LS-DYNA software. The definition of a robust numerical model allowed to evaluate the possibility of buckling triggering. The test article was equipped with potting supports on both ends of the tested beam, filling the pots with epoxy resin toughened with glass fiber nanoparticles. This allowed to uniformly load the beam ends in compression and to carry out the tests loading the specimen statically and dynamically, to observe the differences in the behaviour of the beam under two different types of applied load. The comparison between the numerical and the experimental results shows that the dynamic buckling was triggered by a quantitatively smaller load than in the static case. On the other hand, it is observed this phenomenon to postpone the failure of the structure, due to the significantly higher displacement with respect to the quasi-static case to reach that condition.

Experimental study of the static and hysteretic performance of grouted steel beam-column inter-connections for modular integrated construction

Modular Integrated Construction (MiC) has gained prominence as a construction method, and the integrity of its structural connections plays a critical role in ensuring the overall stability and safety of buildings. This paper presents an experimental investigation into the static and hysteretic performance of grouted steel beam-column inter-connections designed for MiC. The study examines eight full-scale specimens subjected to both monotonic and cyclic loading conditions, with a focus on failure characteristics, deformation behavior, loading-displacement curves, loading-strain curves, skeleton curves of hysteretic loops, stiffness degradation, and energy dissipation. Key findings of the study include the observation of weld cracking between beam flanges and columns in all specimens, highlighting the necessity of welding quality control to prevent such issues. Grouted connections exhibited superior integrity, with no gap opening or misalignment between upper and lower columns. Additionally, it was found that grouting could enhance the stiffness of certain connections. Removal of diagonal stiffeners significantly decreased peak bearing capacity, emphasizing their importance. The composite action brought about by bolts connecting ceiling and floor beams also proved influential. According to Eurocode 3, all grouted specimens fall under the classification of semi-rigid connections, with a distinction made for partial and full-strength connections. This research contributes valuable insights into the static behavior and hysteretic performance of grouted steel beam-column inter-connections for MiC, providing essential knowledge for the structural design and safety of buildings utilizing this innovative construction method.

Refined Stringer Ratings for Girder–Stringer Floor Beam Bridges

Refined Stringer Ratings for Girder–Stringer Floor Beam Bridges

Structural capacity of a composite slim-floor beam with hollow steel tube shear connectors

A slim-floor composite beam’s structural performance relies on the composite action provided by shear connectors. However, the information on the performance of composite slim-floor beam with HSTs connectors in flexural in term of moment capacity, shear interaction and ductility still needs to be clarified. Thus, six specimens of the composite beams with square and rectangular HSTs with two different beam sections, I and inverted T, were tested. The main failure was found to be concrete crushing in the area of the connectors. HST connectors prevented the concrete slab from uplifting, particularly in the specimens without a top flange. Subsequently, this increased moment capacity to 230% and 152% for inverted T and I-beam sections, respectively. Furthermore, ductility behavior was also improved and met EC4 requirements. The degree of shear interaction was increased from 0.4 up to 0.9 compared to the beam without HST. The predicted results from the suggested procedure to estimate moment capacity agreed well with the experimental results, with a maximum difference of 7% in the I-section specimen. In contrast, the predicted value for the inverted T specimen overestimates about 26%. Overall, the beam with the HST shear connector significantly improved the flexural performance of the composite slim floor beam.

Advanced Strengthening of Steel Structures: Investigating GFRP Reinforcement for Floor Beams with Trapezoidal Web Openings

Enhancing existing steel structures becomes imperative upon alterations in usage or geometric configurations, such as introducing web openings in floor beams to accommodate various services. The utilization of welded steel plate and conventional strengthening methods often presents challenges, which may be mitigated through the adoption of composite materials like Fiber Reinforced Polymers (FRP). However, research on the application of FRP to steel beams with web openings remains limited, predominantly focusing on beams with rectangular openings of modest dimensions. This study delves into the application of Glass Fiber Reinforced Polymers (GFRP) to strengthen reinforced steel floor beams featuring trapezoidal openings. Leveraging a rigorously validated numerical model derived from previously published findings by a contributing researcher, the investigation showcases that the proposed GFRP reinforcement scheme exhibits performance comparable to conventional steel plate welding techniques, while preserving the inherent strength of the original solid beams.

Hot spot stress distribution and fatigue life evaluation of steel-UHPC deck in a long-span cable-stayed bridge

The steel-UHPC composite deck is an effective solution to fatigue cracks of orthotropic steel decks (OSD) in steel bridges. However, limited research has been reported on the hot spot stress distribution of the steel-UHPC composite deck. This study investigates the hot spot stress distribution and residual fatigue life evaluation of the steel-UHPC deck in a long-span cable-stayed bridge. The two extrapolation points' strain at fatigue-prone details were continuously measured under in-service traffic flow. The hot spot stress time history at each detail of the conventional OSD deck and steel-UHPC deck were analyzed and compared. The residual fatigue life of each detail was calculated. A three-dimensional finite element (FE) model was established and validated through experimental results. The bridge deck's deflection, the asphalt pavement's tensile stress, and the stress distribution at the floor beam cutout were numerically studied using the validated FE model. The results showed that the UHPC layer significantly reduced the hot spot stress and extended the fatigue life at each fatigue detail. The UHPC layer reduced the bridge deck's deflection and the asphalt pavement's tensile stress. Compared with nominal stress method, the hot spot stress method can better describe the large stress gradient distribution induced by the stress concentration at fatigue detail.