scholarly journals Fire resistance of extruded hollow-core slabs

2017 ◽  
Vol 8 (3) ◽  
pp. 324-336 ◽  
Author(s):  
Kristian Hertz ◽  
Luisa Giuliani ◽  
Lars Schiøtt Sørensen
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Hollow Core ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Standard Fire ◽  
Comprehensive Test ◽  
Building Components ◽  
First Time

Purpose Prefabricated extruded hollow-core slabs are preferred building components for floor structures in several countries. It is therefore important to be able to document the fire resistance of these slabs proving fulfilment of standard fire resistance requirements of 60 and 120 min found in most national building regulations. The paper aims to present a detailed analysis of the mechanisms responsible for the loss of load-bearing capacity of hollow-core slabs when exposed to fire. Design/methodology/approach Furthermore, it compares theoretical calculation and assessment according to the structural codes with data derived from a standard fire test and from a thorough examination of the comprehensive test documentation available on fire exposed hollow-core slabs. Findings Mechanisms for loss of load-bearing capacity are clarified, and evidence of the fire resistance is found. Originality value For the first time, the mechanisms responsible for loss of load-bearing capacity are identified, and test results and calculation approach are for the first time applied in accordance with each other for assessment of fire resistance of the structure.

Study on the Data-Bases for Fire Engineering Design of Structural Steels Members

2012 ◽  
Vol 628 ◽  
pp. 156-160
Author(s):  
In Kyu Kwon ◽  
Hyung Jun Kim ◽  
Heung Youl Kim ◽  
Bum Yean Cho ◽  
Kyung Suk Cho
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Engineering Method ◽  
Fire Tests ◽  
Structural Members ◽  
Data Bases ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
In Fire ◽  
Resistance Performance

Structural steel has been used since the early 1970’s in Korea as primary structural members such as columns, beams, and trusses. The materials have much higher strength such as fast construction, high load bearing capacity, high construction quality but those have a fatal weakness as well. Load-bearing capacity is going down when the structural members are contained in fire condition. Therefore, to protect the structural members made of steels from the heat energy the fire resistance performance required. Generally, the fire resistance performance have evaluated from the exact fire tests in fire furnaces. But the evaluation method takes much more time and higher expenses so, the engineering method requires. The engineering method not only adopts a science but also an engineering experience. In this paper, to make various data-bases for evaluation of structural members such as columns(H-section, RHS), beams, loaded fire tests were conducted and derived not only each limiting temperature but also fire resistance respectively.

FITNET FFS Methodologies for the Assessment of Low Constraint Conditions: Overview, Contents and New Contributions

2008 ◽  
Author(s):  
Sergio Cicero ◽  
Federico Gutie´rrez-Solana ◽  
Mustafa Kocak
Keyword(s):  
Fracture Mechanics ◽  
Bearing Capacity ◽  
Structural Integrity ◽  
Assessment Procedure ◽  
Notch Effect ◽  
Load Bearing Capacity ◽  
Critical Crack ◽  
Load Bearing ◽  
Low Constraint ◽  
First Time

In the last years constraint has represented one of the major issues on fracture mechanics and structural integrity research. The need of more adjusted less conservative (and still safe) assessments requires, in many cases, the consideration of the constraint conditions in the crack tip in order to make better predictions of the load bearing capacity or the critical crack dimensions. The newly developed FITNET FFS Procedure gathers a comprehensive set of methodologies for the assessment of low constraint conditions, from those ones that have their origin on the crack shallowness and/or the type of loading (something that is also treated in other procedures), to those related to the notch effect (included for first time in an assessment procedure). Moreover, one of the biggest difficulties that has been traditionally found when performing constraint assessments, has been the obtainment of the different material and constraint parameters that have to be implemented in the calculations. FITNET FFS has dedicated special efforts in providing values of these parameters for a wide variety of materials and geometries, so that the application of its constraint assessment methodologies is noticeably simplified if compared to other procedures. This paper presents these FITNET FFS constraint methodologies and the advances achieved by the procedure in the constraint field.

Parametric design of surface textures on journal bearing

2015 ◽  
Vol 67 (4) ◽  
pp. 359-369 ◽  
Author(s):  
Hui Zhang ◽  
Guangneng Dong ◽  
Meng Hua ◽  
Feifei Guo ◽  
Kwai Sang Chin
Keyword(s):  
Bearing Capacity ◽  
Journal Bearing ◽  
Parametric Design ◽  
Load Bearing Capacity ◽  
Rectangular Array ◽  
Load Bearing ◽  
Content Type ◽  
Surface Textures ◽  
Capacity Enhancement ◽  
Hydrodynamic Influence

Purpose – The main purpose of this paper is to understand and model the hydrodynamic influence of surface textures on journal bearings. Design/methodology/approach – In the model, a rectangular array of circle dimples is used to modify the film thickness expression. In full film and cavitation regions, classical Reynolds equation and Reynolds boundary condition are used as the governing equations, respectively. By setting high load bearing capacity as the main optimal goal, the influence of textures on tribological characteristics is studied to get the optimal distribution and parameters of textures. Findings – The results suggest that the load bearing capacity of a journal bearing may be improved through appropriate arrangement of textures partially covering its sleeve. The reduction of the cavitation area may also be achieved by arranging the textures in divergent region. With a high density distribution of textures which have step depths varying linearly along the circumferential direction of the bearing, the load bearing capacity enhancement seems to give good performance. Comparing with smooth bearing, the load bearing capacity enhancement of such textures is about 56.1 per cent, although the influence of texture diameters for the same area density seems insignificant. Originality/value – The paper shows how surface textures can be designed on journal bearing to improve its tribological performances.

Load-bearing capacity and resonance stability of inelastic beams and plane trusses with initial defects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dragan D. Milašinović ◽  
Ljiljana Kozarić ◽  
Smilja Bursać ◽  
Miroslav Bešević ◽  
Ilija Miličić ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Damage Mechanics ◽  
Ductile Material ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Stability Problems ◽  
Material Defects ◽  
Fundamental Frequencies ◽  
Stiffness Reduction

PurposeThe purpose of this paper is to contribute to the solution of the buckling and resonance stability problems in inelastic beams and wooden plane trusses, taking into account geometric and material defects.Design/methodology/approachTwo sources of non-linearity are analyzed, namely the geometrical non-linearity due to geometrical imperfections and material non-linearity due to material defects. The load-bearing capacity is obtained by the rheological-dynamical analogy (RDA). The RDA inelastic theory is used in conjunction with the damage mechanics to analyze the softening behavior with the scalar damage variable for stiffness reduction. Based on the assumed damages in the wooden truss, the corresponding external masses are calculated in order to obtain the corresponding fundamental frequencies, which are compared with the measured ones.FindingsRDA theory uses rheology and dynamics to determine the structures' response, those results in the post-buckling branch can then be compared by fracture mechanics. The RDA method uses the measured P and S wave velocities, as well as fundamental frequencies to find material properties at the limit point. The verification examples confirmed that the RDA theory is more suitable than other non-linear theories, as those proved to be overly complex in terms of their application to the real structures with geometrical and material defects.Originality/valueThe paper presents a novel method of solving the buckling and resonance stability problems in inelastic beams and wooden plane trusses with initial defects. The method is efficient as it provides explanations highlighting that an inelastic beam made of ductile material can break in any stage from brittle to extremely ductile, depending on the value of initial imperfections. The characterization of the internal friction and structural damping via the damping ratio is original and effective.

Research on the Mechanical Properties of Fire-Damaged Reinforced Concrete Columns Strengthened with CFRP

2012 ◽  
Vol 193-194 ◽  
pp. 1429-1435
Author(s):  
Dong Liang Qiu ◽  
Kai Yu ◽  
Guo Feng Wang ◽  
Jun Hua Li
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Temperature Control ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing ◽  
Standard Fire ◽  
Reinforced Polymer

The mechanical properties of fire-damaged reinforced concrete columns rehabilitated by carbon fiber-reinforced polymer (CFRP) rods were studied. This study aims at the effectiveness of CFRP through the contrast test. Nine specimens were tested, including three normal temperature control specimens, and six specimens heated under ISO834 standard fire. After the specimens were exposed to fire, three of them were rehabilitated by CFRP. All specimens were loaded monotonically to failure in the same way. The results showed that the failure of reinforced concrete columns rehabilitated by CFRP was due to losing stabilization, whereas the others were material broken. Furthermore, because of the fire, the load-bearing capacity of specimens was all declined sharply compared with these at normal temperature. From this research, comparing with these normal temperature control specimens, the load-bearing capacity of specimens exposed to fire firstly was ranged from 0.25 to 0.37 times. But the ratio of the loading capacity of specimens rehabilitated by CFRP and normal temperature control ones was ranged from 0.54 to 0.67.

Deflection behavior and load-bearing period of structural glued laminated timber beams in fire including cooling phase

2018 ◽  
Vol 9 (4) ◽  
pp. 287-299
Author(s):  
Hitoshi Kinjo ◽  
Yusuke Katakura ◽  
Takeo Hirashima ◽  
Shuitsu Yusa ◽  
Kiyoshi Saito
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Shear Failure ◽  
Fire Performance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Glued Laminated Timber ◽  
Cooling Phase ◽  
Timber Beams

Purpose This paper aims to discuss the fire performance of glulam timber beams based on their deflection behavior and load-bearing period, which were obtained from load-bearing fire tests under constant load conditions. Design/methodology/approach In this report, the fire performance, primarily deflection behavior and load-bearing period of glued laminated (glulam) timber beams will be discussed from the standpoint of load-bearing fire tests conducted during the cooling phase under constant load conditions. Then, based on the charring depth and the per section temperature transformation obtained from loading test results, the load-bearing capacity of the glulam timber beams will be discussed using the effective section method and the strength reduction factor, which will be calculated in accordance with the European standards for the design of timber structures (Eurocode 5). Findings In the cooling phase, the charring rate is decreases. However, as the temperature in the cross section rises, the deflection is increases. The failure mode was bending failure because of tensile failure of the lamina at the bottom of the beam. Moreover, a gap caused by shear failure in a growth ring in the beam cross-section in the vicinity of the centroid axis was observed. Shear failure was observed up until 1 to 3 h before end of heating. The calculated shear strength far exceeded the test results. Shear strength for elevated temperature of glued laminated timber is likely to decrease than the shear strength in Eurocode 5. Originality/value Unlike other elements, a characteristic problem of timber elements is that their load-bearing capacity decreases as they are consumed in a fire, and their bearing capacities may continue to degrade even after the fuel in the room has been exhausted. Therefore, the structural fire performance of timber elements should be clarified during not only the heating phase but also the subsequent cooling phase. However, there are few reports on the load-bearing capacity of timber elements that take the cooling phase after a fire into consideration.

scholarly journals THERMAL INSULATION OF SINGLE LEAF FIRE DOORS, Test results comparison in standard temperature-time fire scenario for different types of doorsets

2016 ◽  
Author(s):  
Daniel Izydorczyk ◽  
Bartłomiej Sędłak ◽  
Paweł Sulik
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Heat Radiation ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Fire Propagation ◽  
Single Leaf ◽  
Rescue Team ◽  
Exposure Temperature ◽  
Temperature Time

<p>Fire resistant door assemblies (doors) for pedestrian or industrial traffic with frame, leaf or leaves, rolled or folded curtain etc. are designed for installation in the openings of the building’s vertical internal partitions. The building and its associated equipment shall be designed and made so that in case of fire it ensures the necessary load bearing capacity of the structure for the time specified in national regulations, limitation of fire and smoke propagation within the building, limitation of fire propagation onto the adjacent buildings and evacuation of people, and it provides safety of the rescue teams. The mentioned requirements are not usually considered individually (e.g. ensuring proper evacuation is connected with the structural load bearing capacity, fire and smoke propagation within the building, and rescue team safety), therefore individual elements of buildings can play several roles during a fire.</p><p>This also refers to the building elements such as doors which are usually required in terms of design and execution to ensure that in case of fire they shall, for a specific period of time prevent its development from the room or a specific zone where the fire started to other rooms or zones, allow evacuation of people by limiting heat radiation, and facilitate rescue team activities. Therefore, fire doors have a major role in the fulfillment of the rules of buildings fire safety.</p>This paper discusses the main issues related to the fire resistance of fire doors (tests methodology and way of classification) and presents a comparison of temperature rises on unexposed surface of fire doors test specimens depending on the type of structure and side of fire exposure. Temperature rises have been compared on unexposed surface of timber, aluminum and steel single leaf doorset which have fulfill the requirements of the EI<sub>2</sub> 30 fire resistance class, in case of the fire acting from the hinge side and the side opposite to the hinges.

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