Deflection Ductility Research Articles

Strength and ductility behaviour of FRC beams strengthened with externally bonded GFRP laminates

The repair and rehabilitation of structural members are perhaps one of the most crucial problems in civil engineering applications. One of the advanced techniques of strengthening the reinforced concrete members is done by fiber-reinforced polymer composites. FRP is very effective to repair and strengthen the structural members that have become structurally weak over their life span. FRP repair system provides an economically viable alternative to traditional repair systems and materials. This experimental study focuses on the flexural strengthening of fiber reinforced concrete beams externally bonded with FRP laminates of different thicknesses. Six beams were cast for the study and tested under a four-point bending system. Out of which two beams were served as a control beam, one beam was considered as a reinforced concrete beam and the other was fiber reinforced concrete beam. The fibers used in this investigation were steel fiber. The beams were strengthened with GFRP of 3 mm and 5 mm of woven roving type. The study parameters of this investigation included yield load, ultimate load, deflection, yield load deflection, ultimate load deflection, deflection ductility, energy ductility, and the beam was found to be very effective in the load-carrying capacity, deflection, and ductility when compared to the control specimen. The fiber-reinforced concrete beam exhibit an increase in ultimate deflection by 79.3% when compared to the control specimen. GFRP strengthened beams showed an increase in ultimate deflection by 18.75% to 94.06%. GFRP strengthened fiber reinforced concrete beams showed an increase in ultimate deflection by 7.8 to 13.125%. GFRP strengthened beams showed an increase in ultimate deflection by 54.7% to 81.88%. GFRP strengthened fiber reinforced concrete beams showed an increase in ultimate load-carrying capacity by 36.9% to 48.7%. The ductility for the specimens increases by 1.27% to 1.34%, compared to the controlled specimen.

Flexural strength and toughness of steel fiber reinforced concrete beams

This study has proposed to evaluate the flexural response of reinforced concrete (RC) beam elements of size 150 mm × 200 mm × 1000 mm (with conventional steel rebars of reinforcement ratio of 0.6%) with and without steel fibers of varying reinforcement index (RI) (product of fiber aspect ratio, AR and volume fraction, Vf%). The mechanical strength (compressive, split tensile and prismatic flexural strength) of concrete are ascertained with hooked steel fibers (HSF) and crimped steel fibers (CSF) in RI of 0.25–1.50 in comparison to controlled concrete (CC) with no fibers. RC beams (with and without HSF and CSF of RI = 0.5–1.0) have been tested under flexure and the loads and deflection at first cracking, yielding, peak and ultimate failure points show that the performance of fibrous beams are higher than non-fibrous beams, and CSF is effective than HSF in RC beams. The RC beams with CSF has higher residual strength and toughness (at deflection point, L/150, L being the span), and total absorbed energy than the specimens with HSF. The residual strength and toughness (at L/150) and the total absorbed energy (TAE) of RC beams with HSF and CSF are higher than the control beams (without fibers). The experimental reserve flexural capacity (ERFC) of RC beams ≥ 1.30. The stiffness of the fibrous RC beams at initial pre-cracking, post-cracking and pre-peak stages are higher than the non-fibrous beams. The deflection ductility indices (yield and peak) have shown an increase when RI is increased from 0.5 to 1.0. The flexural test results have shown that addition of HSF and CSF has improved the first cracking, yielding and peak loads of RC beams (at RI = 0.5, 0.6 and 1.0). The crack spacing and width of flexural cracks in the RC beams have reduced due to the addition of steel fibers, and CSF has shown better cracking behavior than HSF in the beams. The equivalent flexural strength (toughness factor) and strength ratio of RC beams (with conventional reinforcement) with CSF are higher than the beams with HSF, and, therefore, crimped fibers are recommended for effective use in construction.

Flexural performance of precast concrete insulated wall panels with various configurations of ductile shear ties

This paper presents an experimental evaluation of the flexural response of non-load bearing precast concrete insulated partially-composite wall panels fabricated with varying layouts of ductile shear ties. The out-of-plane, one-way, single span load-displacement relationship is obtained for each panel via experimental pseudo-static flexural testing using a water bladder apparatus. Panel specimens constructed with several tie layouts are examined for potential improvements in flexural performance relative to current construction methods. The influence of the shear tie pattern, insulation type, and concrete-insulation interface are examined. Results indicate that placement of additional ties in regions with higher shear demands can enhance the overall flexural capacity and ductility of the panel. Test results show good agreement with partially-composite numerical predictions of both flexural capacity and deflection ductility. Panel deformation histories including full deflected shapes are used to develop deformation-dependent load-mass transformation factors for blast-resistant design via dynamic analysis. Lastly, the strain energy of each panel at several flexural load-deflection milestones are calculated as a preliminary approximation of the blast resistance of each panel.

Influence of Shear Reinforcement on Thin Web Pretensioned Concrete Beams

The objective of this paper is to present the results of the experimental study which was carried out on influence of shear reinforcement of pretensioned concrete thin web beams made with M50 grade concrete. Four pretensioned beams B000, B400, B200 and B100 of the same length, cross section and prestress force were fabricated with no stirrups, 400 mm c/c, 200 mm c/c and 100 mm c/c spacing of stirrups, respectively. The effect of varying percentage of shear reinforcement on cracking load, crack propagation, deflection, ultimate capacity, failure mode and beam ductility was examined. Deflection of the each test beam was measured up to ultimate load at an incremental loading of 2.5 tonne (25 kN). The test results were analyzed for cracking loads and ultimate loads and compared with theoretically estimated values. It has been observed that the loads are found to be increased while increasing percentage of web reinforcement. All the shear reinforced beams exhibited delay in appearance of first crack when compared with beam B000. The reason for the delay in the magnitude of first crack load is recognized as the contribution of shear reinforcement arresting the diagonal shear cracks in the shear zone. The energy abortion capacity of the beams increased while decreasing in the stirrup spacing in the shear span. The beam B100 which was reinforced by double the amount of the web reinforcement than the beam B200 showed a satisfactory margin of safety above 1.50 and ductility response of 3.81.

Assessment of performance criteria of reinforced concrete beams retrofitted with FRP fabrics subjected to extreme impulsive loading

The study performed in this paper is limited to the reinforced concrete structures, in which the behavior of reinforced concrete beams retrofitted with FRP fabrics subjected to extreme loading is investigated. In this regard, numerical modeling using finite element software LS-DYNA is carried out. Numerical results are validated against the results of laboratory experiments. Strengthening of beams with an external composite layer of carbon, glass and Kevlar fibers are considered. Common performance criteria of concrete members such as deflection ratio, support rotation, and ductility ratio as well as crack pattern and energy absorption are investigated. Results show full wrapping mode with carbon fibers leads to the most reductions in the growth of flexural cracks as well as flexural-shear cracks along the free span of the beam. The ductility of the beam is reduced in different states of retrofitting, which the greatest amount of ductility reduction is obtained when reinforced with carbon fibers. Elastic and plastic energies absorbed by the retrofitted beam are, respectively, increased and decreased in all of the investigated cases. Retrofitting with carbon fibers in different states shows the largest increase in the absorption of elastic energy and also the greatest reduction in the plastic energy absorption.

Toughened carbon-fiber reinforced epoxy via isophorone diisocyanate amine surface modification

Surface modification of a carbon-fiber reinforced epoxy (CF/E) via isophorone diisocyanate amine (IDA) is investigated. The covalently bonded IDA, engendering a microscopically thin layer (2 μm–50 μm wide), is an exchange chemical reaction after topically spraying polyurea moieties (isocyanate and amine groups) to curing epoxy that is composed of amine and epoxide groups reacting for tc hours (h). Quasi-static nanoindentation, uniaxial tension and uniaxial compression tests reveal that the chemical bond feature of the tunable IDA surface, conceived at low tc, markedly improves damage tolerance in brittle CF/E by significantly supplementing the energy-release rate (fracture toughness). Compression tests revealed that energy absorption and deflection ductility of IDA-modified CF/E, i.e., C-IDA, and prepared at tc = 0 h, are two and five times greater relative to C-IDA at tc = 0.5 h. Tension tests revealed that energy absorption and deflection ductility of C-IDA at tc = 0 h are 150% and 50% greater than C-IDA at tc = 24 h. Micromechanical properties of the IDA reaction include a uniquely distributed reduced elastic modulus (Er), bounded by moduli of pure epoxy and pure polyurea (overspray). The results, in concert with atomic force microscopy (AFM) and non-negative matrix factorization (NMF) results, validate a link between IDA chemistry and mechanical energy transferability. Manifested as damage localization, fractograph analysis also confirms existence of the link, where bridging of individual damage events in CF/E is markedly reduced.

Experimental Study on Mechanical Behavior of Prefabricated PEC Composite Beams Under Cyclic Loading

In this paper, a new type prefabricated partially encased composite beam (PEC beam) using screw arbors instead of stirrups or welded transverse links in ordinary PEC structures to connect the upper and lower steel flange has been proposed. It not only retains the performance advantages of PEC structures, but also greatly enhances the prefabricated degree of structure and simplifies construction process. Twelve beams with and without screw arbors were tested under cyclic loading to study the mechanical behavior of this new type of PEC beams. The major factors considered were shear span ratio (λ = 1.0, 2.0, 3.0 and 4.0), with or without screw arbors and concrete thickness. Test results including failure mode, load–deflection curves (P − Δ curves), characteristic points, ductility and stiffness were introduced and discussed in detail. The test results showed that the failure mode of PEC beams changed from shear failure to bending failure with the increase of shear span ratio, and the asymmetric damage of specimens can be improved by screw arbors. In addition, PEC beams with screw arbors have better ductility and slower stiffness degeneration than those without screw arbors. Potential application value can be seen from this new type of prefabricated PEC beams.

Horizontal Web Reinforcement Configuration Analysis of Deep Beam Capacity and Behavior using Finite Element Modeling

A deep beam is a beam with a small ratio of its shear span to its effective depth. Deep beams at failure under shear mechanism behave as brittle in contrast to the normal beams which become ductile under the flexural mechanism. The shear failure of deeps beams can be prevented by providing a sufficient amount of web shear reinforcements. Providing horizontal web reinforcement to the RC deep beams is a way to increase their capacity to shear. Testing of the studied deep beams was performed by Finite Element Method (FEM) modeling with the aid of ANSYS software. To obtain valid parameters for modeling RC deep beams in FEM modeling, calibrating test have to be done through verification and validation processes. The study results of all studied RC deep beams show that by closing up the spacing between the horizontal web reinforcement results in increment in the ultimate load, while the ultimate deflection and the curvature ductility were found to be decreasing. For RC deep beams, the placing configuration of horizontal web reinforcement at 0.5h-0.7h was found to be efficient for gaining higher values of ultimate deflection and curvature ductility compared to the placing configuration at 0.3h-0.5h with similar values of ultimate load. It was also found that all the specimens’ crack patterns at the first crack state were caused by flexural-tension while at the ultimate state, they were caused by the shear mechanism.

Flower pollination-based optimal design of reinforced concrete beams with externally bonded of FRPS

The optimal design of reinforced concrete beams (RCBs) and structures with an objective of improving the chosen performances is an important problem in the field of construction works. Recently, the concrete beams, structures, and walls are strengthened externally by bonding fiber-reinforced polymer strips (FRPS). Usually, FRPS are employed in rehabilitation of existing beams, bridges, and other structural elements. This article modifies the problem of designing new RCBs with appropriate selection of FRPS with a goal of exploiting the benefits of FRPS such as higher tensile strength, better corrosion resistance, higher stiffness-to-weight ratio, and longer life. It, firstly, proposes an artificial neural network-based mathematical model for assessing the performances of RCBs bonded with FRPS from the data obtained from 69 FRPS-glued RCBs and then develops an optimal design procedure employing flower pollination-based optimization, which is imitated from the pollination process of plants, for obtaining design parameters of FRPS-glued RCBs with a view of enhancing both the ultimate load and the deflection ductility. It presents optimal design parameters of five FRPS-glued RCBs and experimentally validates the performances.

Precast segmental bamboo reinforced concrete beams with bolted connections subjected to flexural loads: an experimental investigation

Indonesia is one of the wealthiest botanically countries in the world. There are more than 130 species of Bamboo can be found in this country. Bamboo is a natural raw material which is one of the fastest growing plants that has many advantages as a construction material. We conducted an experimental investigation to study the performance of the precast segmental bamboo reinforced concrete beams with bolted connections subjected to flexural loads. Tests were carried out on three specimens with dimensions of 120 mm x 150 mm x 1000 mm, consisting of one control beams (BK), one precast segmental bamboo reinforced concrete beam with four bolted connections (BS4), and one precast segmental bamboo reinforced concrete beam with six bolted connections (BS6). We found that the load carrying capacity of precast segmental bamboo reinforced concrete beams with four bolted connections (BS4) and six bolted connections (BS6) had a decrease of 57.99% and 55.62% respectively compared to control beam (BK). Similarly, the deflection ductility index of the precast segmental bamboo reinforced concrete beams with four bolted connections (BS4) and six bolted connections (BS6) had a decrease of 49.78% and 46.59% respectively compared to control beam (BK). Also, we observed that the crack pattern developed in the control beam indicates a flexural failure mechanism while the crack pattern developed in the precast segmental bamboo reinforced concrete beams indicates a shear failure mechanism. As a conclusion, this study will significantly contribute to the growing development of research on the bolted connection system in bamboo reinforced concrete members, especially in Indonesia.

Flexural Behaviour of GGBS-Dolomite Geopolymer Concrete Beams under Cyclic Loading

Geopolymer concrete (GPC) is the most advanced form of concrete amongst the various types of concrete developed so far. This paper aims at investigating the feasibility of using Ground Granulated Blast furnace Slag (GGBS) as a base material for geopolymer concrete. Effect of dolomite, which is a by-product from rock crushing plant on GGBS based GPC, was studied. Maximum compressive strength was obtained when GGBS and dolomite were proportioned at 70:30. Steel fibres were added to geopolymer concrete (SFGPC) to improve the ductile behaviour and its brittleness index was compared with Ordinary Portland Cement (OPC) concrete. Strength and behaviour of GGBS-Dolomite GPC and SFGPC flexural member subjected to cyclic loading are explained in this paper. Steel fibres are added at 0.25%, 0.5% and 0.75% volume fraction of concrete. Properties such as load deflection behaviour, ultimate load, crack width and ductility were compared with OPC concrete beams.

Performance of hybrid carbon and basalt FRP sheets in strengthening concrete beams in flexure

This study presents the bending performance of reinforced concrete (RC) beams strengthened with hybrid carbon and basalt fiber reinforced polymer (CFRP/BFRP) composite sheets. The proposed hybrid system is intended to improve the properties of the strengthening composite material, in which high strength CFRP sheets are combined with ductile BFRP sheets via epoxy adhesive. A total of 10 beams were tested, nine of which were strengthened with different combinations of CFRP and BFRP sheets, and the remaining beam was unstrengthened to serve as a control specimen. The test results indicated clear improvements in the load-carrying capacity and ductility of the strengthened specimens. The range of increase in the ultimate capacity of the hybrid-strengthened beams over that of the control beam specimen was between 66 and 75%. In addition, the deflection ductility indices of the hybrid beams presented an improvement up to 108% compared to those strengthened with CFRP laminates only. Finite element (FE) models were also developed to predict the response and load-carrying capacity of the tested specimens. The models precisely predicted the experimentally obtained load-carrying capacity and associated mid-span deflections at yield and ultimate loads, with a deviation that did not exceed 12%.

Flexural Strengthening and Rehabilitation of Reinforced Concrete Beam Using BFRP Composites: Finite Element Approach

Basalt fiber‐reinforced polymer (BFRP) is adopted widely in recent years in many countries to rehabilitate or strengthen structural elements such as reinforced concrete (RC) beams because it is cheap and it has stellar mechanical performance. By activating the finite element (FE) simulation, the present research submits an extensive study on the strengthening and rehabilitation of damaged full‐scale RC beams due to corrosions in the main reinforcement caused by BFRP sheets. Different parameters were taken into consideration such as corrosion grade, BFRP wrapping schemes, and the number of layers. The flexural performance of the models that build up as the control model and the damaged and the repaired methodologies by BFRP that are adopted and tested by others under the effects of four‐point static loadings were also underwent examination. The full interaction at BFRP‐concrete interface and the full bonding between sheets presupposed were investigated for all models. The numerical analysis findings were compared with the experimental measurements and found to be in good agreement. The current numerical analysis proved that the ultimate load rised by 14.8% in spite of 20% corrosion in the flexural steel rebar under eight layers of BFRP composite and bottom wrapping mode. In addition, under all strategies of wrapping schemes, the findings also indicated that the deflection ductility index noticeably reduced for RC beams with BFRP composites compared to the control beam. Finally, all the results of midspan deflection, crack patterns, and strain response of the composite system were analysed and discussed briefly.

DUCTILITY RESPONSE OF HYBRID FIBRE REINFORCED CONCRETE BEAMS

Abstract: The effect of fibre content on the Strength and ductility behaviour of hybrid fibre reinforced concrete (HFRC) beams having different fibre volume fractions was investigated. The parameters of this investigation included service load, ultimate load, service load deflection, ultimate load deflection, crack width, deflection ductility and energy ductility. The fibre volume fraction (Vf) ranged from 0.0 to 2.0 percent. Steel and polyolefin fibres were combined in different proportions and their impact on the above parameters was studied. The ductile response of hybrid fibre reinforced concrete beams was compared with that of control beam. The test results show that addition of 2.0 percent by volume of hybrid fibres improve the strength and ductility appreciably. Empirical expressions for predicting the strength and ductility of hybrid fibre reinforced concrete (HFRC) are proposed based on regression analysis. A close agreement has been obtained between the predicted and experimental results.

DUCTILITY RESPONSE OF HYBRID FIBRE REINFORCED CONCRETE BEAMS

Abstract: The effect of fibre content on the Strength and ductility behaviour of hybrid fibre reinforced concrete (HFRC) beams having different fibre volume fractions was investigated. The parameters of this investigation included service load, ultimate load, service load deflection, ultimate load deflection, crack width, deflection ductility and energy ductility. The fibre volume fraction (Vf) ranged from 0.0 to 2.0 percent. Steel and polyolefin fibres were combined in different proportions and their impact on the above parameters was studied. The ductile response of hybrid fibre reinforced concrete beams was compared with that of control beam. The test results show that addition of 2.0 percent by volume of hybrid fibres improve the strength and ductility appreciably. Empirical expressions for predicting the strength and ductility of hybrid fibre reinforced concrete (HFRC) are proposed based on regression analysis. A close agreement has been obtained between the predicted and experimental results.

Structural Behavior of Hybrid Reinforced Concrete Exterior Beam Column Joint

The introduction of wide range of novel raw materials and composites are tuning exceptionally the construction industry on its head. The recent research trends majorly intensified on hybrid concept using the varied materials collectively. This study primarily aims at experimentally investigating the response of concrete exterior beam column joint with Hybrid Reinforcement Technique (HRT) for reverse cyclic load conditions. The on-site fabricated, Hand Layup Carbon Fibre Reinforced Polymer (CFRP-HL) stirrups and the conventional steel main reinforcements form a hybrid reinforcement system in this study. The on-site constructed CFRP-HL reinforcement serves as a substitute for pre-fabricated CFRP rebars which has limitations and inflexibility in adapting the construction alterations. In total six types of specimens, a couple of test specimens are strengthened with HRT and another with external bond CFRP fibre wrap. In the remaining three specimens, one with non-conventional steel detailing and a couple of conventional joints that are designed according to IS 456:2000 and IS 13920:1993 respectively. In addition, the influence of varied spacing of stirrups in specimens is studied separately. Further, the test results on overall strength, stiffness, load deflection characteristics, dissipated energy and ductility of test specimens is evaluated and discussed. The use of CFRP-HL with steel as hybrid combination enables to comprehend the benefit from their distinctive characteristics. This proposal strongly improves the greater flexibility of using CFRP-HL in field as needed.

Deflection Ductility of Slabs Made of Hybrid Mesh-And-Fibre-Reinforced Cementbased Composite

Abstract Steel Mesh-Reinforced Cementitious Composites (SMRCC) (traditionally known as ferrocement) have been in existence for few decades, but have some limitations set on element thickness and number of reinforcing mesh layers and the resulting deflection ductility. Therefore, the author has made an attempt to explore whether deflection ductility will improve in mesh-reinforced cementitious composites (25 mm thick) if discontinuous fibres are added to slab elements. For this purpose, thin slab elements of dimensions 700 mm (length) × 200 mm (width) × 25 mm (thickness) were cast and subjected to four point bending tests. Based on the flexural tests conducted on SMRCC (Control Slab Elements, cast with Steel Mesh Volume of reinforcement, MVr=0.78, 0.94, and 1.23%) and Hybrid Mesh-and-Fibre-Reinforced Cement Based Composite (HMFRCBC) (Test Slab Elements, combining MVr=0.78, 0.94 and 1.23% and Polyolefin Fibre Volume fraction, PO-FVf=0.5-2.5% of volume of specimens, with 0.5% interval), load-deflection and the deflection ductility index were analyzed. From the flexural load-deflection curves it has been observed that HMFRCBC slabs demonstrate higher flexural load-carrying capacity and deflection ductility when compared to SMRCC slabs. This study shows that higher the polyolefin fibre volume fraction (PO-FVr) from 0.5 to 2.5% (with a 0.5% interval) in HMFRCBC slabs, the higher the flexural deflection ductility. The Deflection Ductility Index (DDI) of HMFRCBC (with 5 layers of mesh and PO-FVr=2.5%) is 4.5 times that of SMRCC. This study recommends that HMFRCBC can be used as an innovative construction material due to its higher flexural ductility characteristics.

NEAR SURFACE MOUNTED BAMBOO REINFORCEMENT FOR FLEXURAL STRENGTHENING OF REINFORCED CONCRETE BEAMS

Near Surface Mounted (NSM) is a technique performed for the installation of strengthening material into grooves cut into the concrete cover of reinforced concrete (RC) beams bonded using a bonding agent. This technique is becoming more widely recognized because of its efficiency, effectiveness, and ease of application. We investigated flexural strengthening of RC beams with the NSM technique using bamboo reinforcements, through both experimental tests and a finite element analysis (FEA). The experimental tests were carried out on three RC beams, one consisting of a control beam, and the other two strengthened by the NSM technique with two steel reinforcements, and four bamboo reinforcements. From the experimental tests, we found that the flexural strength of the beam with NSM bamboo reinforcements was increased by 41.7% and the deflection ductility index was reduced by 21.55%. The mode of failure observed in all the strengthened beams was a flexural failure. Finally, the result of FEA behaved similarly to the results of the experimental test.

Influence of polypropylene fibers on the flexural behavior of reinforced concrete slabs with different opening shapes and sizes

The effect of polypropylene fibers (PF) on the flexural behavior of reinforced concrete one‐way slabs with opening was investigated in this paper. The evaluated parameters included four different PF volume percentages (0, 0.3, 0.6, and 0.9%), with and without opening, two opening shapes (square and circular), and three opening sizes (100, 150, and 200 mm). Three groups of tested slabs were casted: without opening, with square opening, and circular opening, resulting in a total of 28 slabs. The behavior of each slab was evaluated in terms of the cracking load, ultimate capacity, initial and yielding stiffness, deflection ductility, and energy ductility. In addition, the steel and concrete strains, crack opening, and mode of failure were measured and monitored. The minimum design load capacities were calculated theoretically based on the sectional analysis and compared with the tested ones. The results showed that the use of PF at percentages greater than 0.6% significantly enhanced the performance parameters of the slabs with small opening size (2% opening ratio) and provided acceptable enhancement for slabs with large opening size (8% opening ratio). Therefore, the PF can be optimized to substitute the conventional steel reinforcement of slabs with small openings, especially circular openings.

Strength Analysis of Reinforced Concrete Beams Affected by Fire Using Glass Fiber Sheet and PP Fiber ECC as Binders

Flexure study on (100 mm × 150 mm × 1500 mm) unstrengthened fire-affected (FD) beams and strengthened fire-affected (FDS) beams is presented in this paper. The parameters considered were different intensities of fire, load deflection behavior, spalling, crack pattern, stiffness, ductility and energy absorption. The three phases (300, 500 and 900 °C) of ISO834 fire curve were achieved in oil-burnt furnace of 250 kg capacity. The cooled beams were repaired for cracking and spalling and cured. The strengthening of repaired beams was achieved using glass fiber sheet with PP ECC (polypropylene engineered cementitious concrete) as binders. Numerical thermal stress analyses were carried out (ANSYS) for a thermal load of 300 °C. Data from flexure test showed that strengthening was effective for beam members affected by fire up to 500 °C, by shifting brittle shear failure to ductile flexural failure and improving the stiffness, energy absorption and ductility. Strengthening could not enhance the load deflection behavior and could not stop brittle shear failure if the fire loading in members exceeded 500 °C. Present technique could restore the strength and stiffness in members affected by medium fire intensity in an effective way, without carrying out any major repair for the damages.