Fire Resistance of In-Plane Compressed Log-House Timber Walls with Partial Thermal Insulation

This paper presents the full-scale experimental assessment of a log-house timber wall with partial thermal insulation under in-plane compression and exposed to fire on one side. A key aspect of the current design application for log-house systems is represented by geometrical details, like cross-sectional properties of logs (typically characterised by high depth-to-width ratios) and outriggers. The latter provides restraint condition for the examined walls and hence markedly affects their overall load-carrying capacity. As a result, careful consideration should be given to the choice of these details, compared to fully monolithic timber walls (i.e., made from cross-laminated timber), due to the possible occurrence of local structural and/or thermo-mechanical mechanisms. This is the case of exceptional loading conditions like fire load, as the fire resistance of these systems could be affected by a multitude of variables, including the presence (even though limited to few surfaces only) of thermal insulation panels. To this aim, the results of a full-scale furnace test are discussed in the paper for a log-wall with partial thermal insulation, namely thermal insulation applied on the outriggers only, under the effects of EN/ISO standard fire conditions. The results of Finite Element (FE) numerical studies are also reported, to further explore the load-carrying performance of the reference log-house specimen and compare it with the experimental observations. Several thermal insulation configurations are finally numerically investigated, showing their effects on the overall fire resistance of the assembly. In accordance with literature, the test shows that the log house’s timber wall is suitable to obtain a fire resistance of about 60 min under relevant loading. The FE results are in rather close agreement with the temperature measurements within the section of logs, as well as a qualitative correlation with respect to the mechanical behaviour observed in the full-scale furnace experiment. The key role of outriggers and their thermo-mechanical boundaries, finally, is emphasised.

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Experimental study on fire resistance of a full-scale composite floor assembly in a two-story steel framed building

Journal of Structural Fire Engineering ◽

10.1108/jsfe-05-2021-0030 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Lisa Choe ◽

Selvarajah Ramesh ◽

Xu Dai ◽

Matthew Hoehler ◽

Matthew Bundy

Keyword(s):

Natural Gas ◽

Fire Resistance ◽

Full Scale ◽

System Level ◽

Compartment Fire ◽

Content Type ◽

Standard Fire ◽

Fire Experiment ◽

The Usa ◽

Floor System

PurposeThe purpose of this paper is to report the first of four planned fire experiments on the 9.1 × 6.1 m steel composite floor assembly as part of the two-story steel framed building constructed at the National Fire Research Laboratory.Design/methodology/approachThe fire experiment was aimed to quantify the fire resistance and behavior of full-scale steel–concrete composite floor systems commonly built in the USA. The test floor assembly, designed and constructed for the 2-h fire resistance rating, was tested to failure under a natural gas fueled compartment fire and simultaneously applied mechanical loads.FindingsAlthough the protected steel beams and girders achieved matching or superior performance compared to the prescribed limits of temperatures and displacements used in standard fire testing, the composite slab developed a central breach approximately at a half of the specified rating period. A minimum area of the shrinkage reinforcement (60 mm2/m) currently permitted in the US construction practice may be insufficient to maintain structural integrity of a full-scale composite floor system under the 2-h standard fire exposure.Originality/valueThis work was the first-of-kind fire experiment conducted in the USA to study the full system-level structural performance of a composite floor system subjected to compartment fire using natural gas as fuel to mimic a standard fire environment.

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Fire Resistance Behavior of Full-scale Self-thermal Insulation Sandwich Walls Made of Textilereinforced Concrete

International Journal of Heat and Technology ◽

10.18280/ijht.370129 ◽

2019 ◽

Vol 37 (1) ◽

pp. 239-248

Author(s):

Linghua Shen ◽

Jiyang Wang ◽

Shilang Xu ◽

Godwin Amoako-Atta

Keyword(s):

Thermal Insulation ◽

Fire Resistance ◽

Full Scale

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Performance of isolated and folded footings

Journal of Computational Design and Engineering ◽

10.1016/j.jcde.2016.09.001 ◽

2016 ◽

Vol 4 (2) ◽

pp. 150-157 ◽

Cited By ~ 1

Author(s):

Mahmoud Samir El-kady ◽

Essam Farouk Badrawi

Keyword(s):

Reference Sample ◽

Cross Sectional ◽

Tensile Stresses ◽

Numerical Studies ◽

Flat Shape ◽

Load Carrying ◽

Heavy Loads ◽

Concrete Footing ◽

The Cost ◽

Good Agreement

Abstract Folded foundations have been used as an alternative to the conventional flat shallow foundations, in situations involving heavy loads or weak soils. They can be geometrically shaped in many forms especially for isolated footings. The purpose of this paper is introducing an alternative foundation shape that reduces the cost of foundations by reducing the amount of reinforcing steel by minimizing or even eliminating the tension zones in the folded isolated footings. Also, achieving lower soil stresses through changing the isolated footing shape will consequently reduce the expected settlements and the footing stresses. Experimental and numerical studies are performed on five (5) quarter scale footings of which one (1) footing of flat shape is tested as a reference sample and four (4) footings are of folded shape by folding angles of 10°, 20°, 30°, and 40° with the horizontal. Results showed that the folded isolated footings achieve economic design by decreasing the quantities of reinforcement. It also induced less soil settlements, and stresses. In addition, the tensile stresses in the reinforced concrete footing body are also less in folded isolated footings than the flat one. Results show that the folded isolated footing have a better load carrying capacity when compared with the conventional slab/flat footing of similar cross sectional area for both cases of experimental and numerical analysis. Highlights The purpose of this paper is achieving lower soil stresses through changing the isolated footing shape will consequently reduce the expected settlements and the footing stresses resulting from differential settlements. Experimental and numerical studies are perform using five (5) quarter scale footings of which one (1) footing of flat shape as a reference sample and four (4) footings are of folded shape by a folding angles of 10, 20, 30, and 40 degrees with the horizontal. The most effective and preferable value of the folding angle (?), is equal to 30 degrees. Good agreement is reached between the experimental and numerical results. Results showed that the maximum tensile stresses in steel bars decreased by about 48% for folded isolated footing case when compared with conventional flat ones

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Fire Resistance of Reinforced Concrete Corrosion-Damaged Columns of the "Standard" Fire

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.828.163 ◽

2019 ◽

Vol 828 ◽

pp. 163-169

Author(s):

Ashot Georgievich Tamrazyan ◽

Micheal Sergeevich Mineev ◽

Aishat Urasheva

Keyword(s):

Reinforced Concrete ◽

Bearing Capacity ◽

Fire Resistance ◽

Protective Layer ◽

Operating Conditions ◽

Corrosive Environment ◽

Reinforced Concrete Column ◽

Cross Sectional ◽

Standard Fire ◽

The Cross

The article describes the features of the effect of corrosion of reinforcement on the bearing capacity of reinforced concrete columns in a "standard" fire. On the basis of the standard calculation method, the fire resistance of the column was estimated under a four-sided fire effect taking into account the different duration of the fire. The study examined the operation of the column in a corrosive environment, it was assumed that the initiation of corrosion of concrete and reinforcement will occur after 10 years of exploitation. It was found that the destruction of concrete protective layer 25 mm thick in a medium aggressive environment will occur after 25 years, and the diameter of the reinforcement during this period will decrease by 20%. To compare the results, a reinforced concrete column with a section of 400x400mm was calculated under the influence of a “standard” fire under normal operating conditions and taking into account work in a corrosive environment. The results of heat engineering calculations are presented, where the temperature changes in the reinforcement depending on the heating time and reduction of the protective layer thickness, as well as the change in the diameter of the reinforcement and its effect on the bearing capacity are shown. It has been established that reducing the cross-sectional area of the working reinforcement and reducing the cross-sectional dimensions of the column due to the occurring corrosion processes leads to a decrease in the fire resistance limit on the loss of bearing capacity by 58%.

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Experimental Study on Delaying the Failure Time of In-Service Cables in Trays by Using Fire-Retardant Coatings

Applied Sciences ◽

10.3390/app11062521 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2521

Author(s):

Feng Jiang ◽

Jianyong Liu ◽

Wei Yuan ◽

Jianbo Yan ◽

Lin Wang ◽

...

Keyword(s):

Fire Resistance ◽

Failure Time ◽

Fire Retardant ◽

Resistance Test ◽

Control Group ◽

Engineering Practice ◽

Standard Fire ◽

Oil Storage ◽

Fire Resistance Test ◽

Test Furnace

Improving the fire resistance of the key cables connected to firefighting and safety equipment is of great importance. Based on the engineering practice of an oil storage company, this study proposes a modification scheme that entails spraying fire-retardant coatings on the outer surface of a cable tray to delay the failure times of the cables in the tray. To verify the effect, 12 specimens were processed using five kinds of fire-retardant coatings and two kinds of fire-resistant cotton to coat the cable tray. The specimens were installed in the vertical fire resistance test furnace. For the ISO 834 standard fire condition, a fire resistance test was carried out on the specimens. The data for the surface temperature and the insulation resistance of the cables in trays were collected, and the fireproof effect was analyzed. The results showed that compared with the control group, the failure time of the cable could be delayed by 1.57–14.86 times, and the thicker the fire-retardant coatings were, the better the fireproof effect was. In general, the fire protection effect of the fire-retardant coating was better than that of the fire-resistant cotton.

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Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption

Nano-Micro Letters ◽

10.1007/s40820-021-00635-1 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Weihua Gu ◽

Jiaqi Sheng ◽

Qianqian Huang ◽

Gehuan Wang ◽

Jiabin Chen ◽

...

Keyword(s):

Microwave Absorption ◽

Thermal Insulation ◽

Freeze Drying ◽

Thermal Infrared ◽

Carbon Aerogel ◽

Carbon Aerogels ◽

List Type ◽

Drying Method ◽

Cross Sectional ◽

Compression Resistance

Highlights The eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method. Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel. Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition. . Abstract Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

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Yacht Keels - An Experimental Study

10.5957/csys-1975-008 ◽

1975 ◽

Author(s):

Pierre DeSaix

Keyword(s):

Experimental Study ◽

Aspect Ratio ◽

Center Of Gravity ◽

Full Scale ◽

Optimum Size ◽

Hull Form ◽

Size And Shape ◽

Aspect Ratios ◽

Current Design ◽

Lateral Area

Model tests are presented for a series of nine keels; three aspect ratios, three sweep angles; all at constant lateral area, taper ratio and thickness ratio. The series is shown to bracket current design trends. These keels are all tested on the same canoe body, over a range of heel angles, lee-ways, and speeds. The results are presented in terms of full-scale sailing performance with due allowance for a reasonable ballast ratio and resulting vertical center of gravity for each keel. Optimum sweep angles for each aspect ratio are found. A second series of three keels, geometrically similar but varying in lateral area, is provided. Predictions of windward performance demonstrate the effect of keel size. An optimum size is found for three wind strengths. The results are for one hull form only. However, a method is suggested for estimating the effect of keel size and shape for any proposed design.

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Full scale test of a PC bridge to calibrate assessment methods

10.2749/ghent.2021.0965 ◽

2021 ◽

Author(s):

Niklas Bagge ◽

Jonny Nilimaa ◽

Silvia Sarmiento ◽

Arto Puurula ◽

Jaime Gonzalez-Libreros ◽

...

Keyword(s):

Prestressed Concrete ◽

Structural Response ◽

Sensitivity Study ◽

Assessment Method ◽

Full Scale ◽

Concrete Bridges ◽

Fractional Factorial ◽

Fe Model ◽

Load Carrying ◽

Existing Bridges

<p>In this paper, experiences on the development of an assessment method for existing bridges are presented. The method is calibrated using the results of full-scale testing to failure of a prestressed bridge in Sweden. To evaluate the key parameters for the structural response, measured by deflections, strains in tendons and stirrups and crack openings, a sensitivity study based on the concept of fractional factorial design is incorporated to the assessment. Results showed that the most significant parameters are related to the tensile properties of the concrete (tensile strength and fracture energy) and the boundary conditions. A finite element (FE) model in which the results of the sensitivity analysis were applied, was able to predict accurately the load-carrying capacity of the bridge and its failure mode. Two additional existing prestressed concrete bridges, that will be used to improve further the method, are also described, and discussed.</p>

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