BUILDING CONDITION ASSESSMENT REPORT A CASE STUDY PDF

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ABSTRACT Building where we live should be strong, looking attractive, and economic. Due to some construction or design or both failure makes building unsafe and loss of money. This is the building assessment of commercial building having bad construction and poor workmanship. PREPARED FOR: Community...

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ABSTRACT Building where we live should be strong, looking attractive, and economic. Due to some construction or design or both failure makes building unsafe and loss of money. This is the building assessment of commercial building having bad construction and poor workmanship.

PREPARED FOR: Community Connect Course (CCU101) Sharda university greater Noida knowledge park2

BUILDING CONDITION ASSESSMENT REPORT A CASE STUDY

PREPARED By: Abhayendra Pratap singh (2019003775) Bahar Abbas Shah (2019543184) Binnu karki (2019006756) Birendra Kumar Bohara(2019000756) Jamsheeed ur Riza (2019007046) Jawid Sharifi (2019001192) Kafeel Hussain (2019006353) Kshitiz Gautam (2019000316) Lanchenba Laishram (2019579258) Submittal Date: April 6, 2020

BUILDING CONDITION ASSESSMENT REPORT: A CASE STUDY A.P. Singh, B. Karki, B. Bohara, J.ur. riza, J. Sharifi, K. Hussain, K. Gautem, L. Laishram. Department of Civil engineering ( M.Tech. Structure Engineering ) sharda University Greater Noida India.

ABSTRACT

This paper based on condition assessment of reinforced concrete structure. The main focused of this assessment is in quality of construction, material, and quality control. There is several defect like segregation, cracking, deflection of slab panel, poor construction practice, poor beam column joint, poor formwork used, corrosion in steel, cover, etc. which makes building more vulnerable and poor earthquake resisting capacity. The building needs lots of repair and maintenance. It also need re strengthen technique to build the load and seismic effect carrying capacity of the structure. By using visual inspection of the building by structural engineering student we conclude that the building need same serious attention in repair, maintenance, re strengthen and providing sufficient cover to protect reinforcement from corrosion.

1. INTRODUCTION Structure engineering group from Sharda University was retained by the Regional District of Uttar Pradesh to perform a visual assessment of the accessible architectural, structural envelope components of the building located at place. The scope of our review was visual in nature and no destructive testing was performed. We have not been asked to provide detailed drawings, site direction, or remediation at this time. The following report outlines the results of our field review, performed on Feb. 6th, 2020. The Owner’s representative, was kind enough to be on site during the assessment to assist with building access and provide an overview of the building layout. Damage assessment try to determine to identify the structural damages has occurred or not. The damage may be caused by crack, surface deterioration, surface deposits, deformation, and construction defects or construction features.it is important to know where and why RC building going to be defect. It is also difficult to know their material properties, original construction quality levels and design standard. Their material properties can be found by using different ways and needs level of knowledge, depends on detailing. Nuno Pereira, Xavier Romão (2016) they conclude the probability – based framework detailing test sampling plans of existing buildings and introduce the CF mat material safety factors leading to mean material strength values that are on the safe side. Quality of concrete in structure depends upon many factors such as method of mixing, transporting, placing, compacting and curing of concrete structure. Concrete members are allowed certain amount of defects it 1|Page

should be obey the strength and serviceability, may not satisfy durability requirement. Durability and service life of structure is mainly governed by microstructure and properties of concrete and environmental parameters to which the structure is exposed [9].

1.1 BUILDING DESCRIPTION   

Single storey Frame structure Basement system Building type: commercial building

2. SCOPE OF BUILDING ASSESSMENT During the review we attempted to examine the site, exterior elevations, roofing, numerous interior rooms and finishes, architectural components assemblies, beam, column element etc. Analysis of beam columns and other structural element and problem analysis and solving these problem as a structural engineering.

3. LITERATURE REVIEW 3.1 Definition of Nondestructive testing (NDT) It is a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive, examination (NDE), nondestructive inspection (NDI), and nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research. There are several research paper to identified the failure of building and as well as finding defect on building construction. Angelo Masi (2016) concern about the identification of concrete homogeneous area. According to researcher the estimation of concrete strength based on limited number of core sampling would not be enough to representative of structure property variations. And they suggest that NDTs are simple and less expensive but when used alone it also provide unreliable prediction of concrete strength. There are several type of NDT test some of given below [9]. (i) visual inspection to identify and locate seepage/dampness areas, cracks, rust stains, rebar exposure, (ii) ultrasonic pulse velocity measurements for assessing concrete quality and integrity (iii) concrete cover thickness survey for identifying low concrete cover zones (iv) core sampling and testing for petrographic examination, water absorption, and evaluation of compressive strength (v) evaluation of half-cell potential, concrete resistivity, chloride permeability and chloride content for assessing the corrosion proneness of rebar (vi) Germann water permeation test (GWT) for assessing the skin concrete permeability based on flow rate (vii) Infrared-thermography (IRT) for scanning large areas of IDCT walls to locate the seepage/dampness areas and also to evaluate the efficacy of the repair schemes for water tightness/impermeability.

3.2 Definition of Steel reinforcement corrosion

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The chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties. For steel embedded in concrete, corrosion results in the formation of rust which has two to four times the volume of the original steel and none of its good mechanical properties. Corrosion also produces pits or the surface of reinforcing steel, reducing strength capacity as a result of the reduced cross sectional area. Corrosion of steel reinforcement is one of serious problem in RC structure and it is difficult to quantify is early stage of development. Electrochemical techniques currently available for nondestructive evaluation method. Shilpa Patil , Bilavari Karkare , Shweta Goyal (2017) introduced new technique acoustic emission (AE) which is based on continuous monitoring technique and location is select based on visual inspection.

3.3 Definition of Retrofitting. Retrofitting is a technique to enhance the structural capacities including the strength, stiffness, ductility, stability, and integrity of a building that is found to be deficient or vulnerable. It can effectively raise the performance of a building against earthquake to a desired level, and to even satisfy the requirements of an upgraded design seismic code. The building need not be deteriorated or damaged. The retrofit is intended to mitigate the effect of a future earthquake. In this the assessment, an effort is made to elaborate the procedure of providing concrete jacketing to the column as per guidelines of IS 15988: 2013. Retrofit of RC beam column is the method to enhance the strength of beam columns. RC jacketed and CFRP (carbon fiber reinforcement polymers), Bond of fiber reinforcement polymers (FRP), Grooving method (GM), etc. are the method to use the re strengthen the beam and columns [8].

3.4 Acceptability Criteria A building is said to be acceptable if either of the following two conditions are satisfied along with supplemental criteria for a particular building type described in is IS15988: 2013. a) All critical elements of lateral force resisting elements have strengths greater than computed actions and drift checks are satisfied. b) Except a few elements, all critical elements of the lateral force resisting elements have strengths greater than computed actions and drift checks are satisfied. The engineer has to ensure that the failure of these few elements shall not lead to loss of stability or initiate progressive collapse. This needs to be verified by a non-linear analysis such as pushover analysis, carried out up to the collapse load.

4 OBJECTIVE OF THE ASSESSMENT The problem of the structural elements of the building and provide suitable selection of an appropriate repair scheme requires a systematic investigation to evaluate/identify the root cause for the problem in structure.

5. RESEARCH METHODOLOGY 5.1 Non-Destructive testing & evaluation (NDT&E) 3|Page

According to authorities the building is constructed in 5 years ago. But due to lack of care building needs lots of repair, maintenance and some part may demolish due to structural failure. Site visit was conducted by structural engineer to analysis the available existing building data and to determine the condition of building and its components. Following information are collected during visit:  General information:  5year of construction  Structural system :  framing vertical lateral force resisting system,  rigid diaphragm roof,  one storey height basement,

5.2 Visual inspection During the visual inspection, construction deficiencies are noticed at many places. Openings/gaps are found at junction between RC columns and top beam. Voids and honeycombing areas in columns; patch repair works especially at shuttering lifts/joints, and uneven RC wall surface, etc. are noticed. Also nominal cover not provided on slab beam and column. Reinforcement are visible, deflection occurs on slabs, insufficient beam columns ratio etc. problem clearly identify in site inspection [9].

a)crack on slab

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b)segregation (honeycomb)

c) honeycombing

d) Poor beam column joint

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5.3 Evaluation Process The evaluation process was conducted as following process: Preliminary Evaluation   

Site visit and collection of data. Configuration-related checks ( Load path, geometry, weak/soft storey, vertical discontinuities, columns beams) Strength-related Check. 1. Determination of modified demand lateral force considering occupancy risk factor and factor for useable life. 2. 2. Shear stress Check in columns and walls. 3. 3. Axial stress check in moment frame columns.

Yes

Acceptability Criteria Satisfied

Detailed Evaluation (For Primary Lateral-Force Resisting System) a) Component Strength using Knowledge Factor. b) Comparing Probable Component Strengths with Expected Seismic Demands. c) Crack and corrosion study and effect. d) Deflection.

Repair or demolish of str. Not recommend

Yes

Acceptability Criteria Satisfied

No

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It may be required. Retrofit Repair Column jacketing Covering etc.

6. DATA DESCRIPTION Data was collected by student of structure engineering. It include both primary and secondary data. The visual inspection of the building which may be used in the analysis the building. The building conduction was not good where construction failure was seen. Honeycombing in concrete, week beam columns joint, bad finishing of concrete member, steel bar clearly seen that sufficient nominal cover was not provided, deflection of slab, beam columns ratio, supervision failure, etc. are the primary data. Books Published papers, IS 15988: 2013, is 456:2000, interview, discussion etc. are the secondary data used in this paper.

7. FINDINGS AND DISCUSSION The building was constructed 5 years ago. There is same failure occurs in structure at construction stage. Poor workmanship and improper implementation of formwork and lack of supervision by export are the some failure at construction stage. Failure analysis is the technique of evaluating data to establish the origin of failure, and recommend the precaution necessary to avoid recurrence. Here are the some finding which effect the strength of building and cause of failure construction of structure. 7.1. Poor Beam- column joint The beam columns joint is most critical zone in a reinforced concrete moment resisting frame. It is subjected large force during earthquake and it significant influence on the response of the structure. So the joint should be designed and constructed properly. Defect seen in the beam column joint are: i) Improper finishing ii) Improper cover. iii) Honeycombing concrete iv) Corrosion of steel

1. Beam column joint

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7.2 Excessive deflection in concrete slab Deflection of reinforced concrete slabs is acceptable to a certain limit which are specified by applicable Codes such as ACI, IS Codes and Euro Codes. These codes to specify the amount of deflection which is acceptable. In the building the deflection is exceeded and it effect the load bearing capacity, cracks are developed in slabs, some reinforced steel clearly seen in the surface of the slab. Also poor construction and finishing and quality assurance.

2) Deflection RC. Slab

7.3. Honeycomb damage in reinforced concrete beams

It is categorized as construction defect which occurs in concrete that is not correctly consolidated due to poor vibrations or poor design of formwork. Voids may occur due to segregation of coarse aggregates, fine aggregates with cement. In this building many part of beam honeycomb structure have founded. Also in beam some part the stirrups and main rebar are seen. Following are the beam and its defect shown in fig.

Fig 3. Main bar & stirrups and honeycombing an 8|Page

fig4 honeycummbing

8 RECOMMENDATION AND CONCLUSIONS Here are the some common defect found in the building 8.1 Honeycombing in RC structure Reasons for honeycombing in columns beam and slabs  Concrete mix not being cohesive.  Poor supervision and workmanship.  Concrete workability not sufficient/ suiting its placement requirement.  Insufficient compaction to concrete.  Steel congestion not allowing concrete flow to all corner.  Concrete already set before placing.  High free fall of concrete, while pouring  Form work not watertight To repair honeycombed concrete surface: 

 

Remove the loose concrete particles and using mechanical injecting pressure pump, Grout the surface with no shrink epoxy grout to fill the micro voids where repair mortar cannot reach. Post grouting apply self –curing repair mortar of equivalent compressive strength. Note the buildup not to be more than 15mm thick. If the voids are large or hollow packets are observed, then the same needs to be treated using micro concrete of equivalent grade. Micro concrete are also available in readymade packages and in different strength grades.

8.2. Beam columns repair also prevent corrosion 9|Page

Hence several problem like poor workmanship, honeycombing, lack of curing, corrosion, lack of nominal cover, rod are rusted, carbonation attack, and poor beam column joint the strength of beam and column is reduced. As visual inspection design of beam columns also poor. Either beam are not properly designed or the construction technique are not proper. Also supervision of building is not done. Beam columns ratio is not sufficient. While looking slab panel one of panel was deflected and other panel also showing not good working condition. Overall building condition is not good. There for either we Strengthening the member or demolish the structure. Corrosion is an electrochemical process, which occurs on metal in presence of both oxygen and water. The latter is contained in the pores of the embedding material and represents the electrolyte that allows the corrosion of the steel reinforcement to take place. Overall it reduces the load carrying capacity of the element.

Re-strengthening of the member (is 15988) For this we have to do detail investigation of beam columns and analysis what type of Retrofitting process we use. 

Reinforced concrete jacketing of columns

Reinforced concrete jacketing improves column flexural strength and ductility. Closely spaced transverse reinforcement provided in the jacket improves the shear strength and ductility of the column. The procedure for reinforced concrete jacketing is as follows: a. The seismic demand on the columns, in terms of axial load P and moment M is obtained. b. The column size and section details are estimated for P and M as determined above. c. The existing column size and amount of reinforcement is deducted to obtain the amount of concrete and steel to be provided in the jacket. d. The extra size of column cross-section and reinforcement is provided in the jacket. e. Increase the amount of concrete and steel actually to be provided as follows to account for losses. ' Ac = (3/2)A’c and As=(4/3)A’s Where Ac and As = actual concrete and steel to be provided in the jacket; A’c and A’s = concrete and steel values obtained for the jacket after deducting the existing concrete and steel from their respective required amount. f. The spacing of ties to be provided in the jacket in order to avoid flexural shear failure of column and provide adequate confinement to the longitudinal steel along the jacket. g. If the transfer of axial load to new longitudinal steel is not critical then friction present at the interface shall be relied on for the shear transfer, which shall be enhanced by roughening the old surface. h. Dowels which are epoxy grouted and bent into 90° hook shall also be employed to improve the anchorage of new concrete jacket. 10 | P a g e

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Fiber jacketing of a beam

Dimensions of FRP jacket is determined assuming composite action between fiber and existing concrete. The rupture strength of FRP is used as its limiting strength. Limit state moment capacity of FRP retrofitted member is given by: Ultimate flexure strength is determined based on the assumption that compressive concrete reaches a strain of 0.003 5 and FRP reaches its maximum strain.

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8.3 carbon-fiber-reinforced polymer (CFRP) This technique is used when beam column joint have no sufficient seismic and load carrying capacity is less to gain strength this method also be used. Several research shows that by using CFRP fabric sheets or plates as strengthening material and using CFRP as a strengthening material led to increased ultimate capacity [3]. CFRP strips and fabric are generally constructed of high-performance carbon fibers which are placed in resin matrix. These composites can easily be externally bonded to RC elements. Strengthening with fiber-reinforced polymeric composite applications is one of the recent retrofitting and strengthening techniques. The other technique fiber-reinforced polymer (FRP) systems are also used in the field of strengthening and restoration of the buildings. The most commonly utilized fiber-reinforced polymers (FRPs) are fibers made of carbon (C) or glass (G). These materials can be designed and used in the form of laminates, rods, dry fibers (sheets) adhesively bonded to the concrete, wet lay-up sheets mounted on the surface, or near surface mounted bars or laminate strips in the concrete cover.

9. CONCLUSIONS When studying the several aspect of building defect and its related sol...