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Luận văn tốt nghiệp năm 2021 ngành xây dựngEurocode In the face of rapidly growing population, population density in Ho Chi Minh City, the more demand for land to build houses, while the city’s land fund is limited, and land prices are escalating, the solution of building high – rise apartments and developing residential planning to districts and suburban areas is a reasonable solution today. In addition, the investment in the construction of tall buildings to replace low – rise buildings, degraded residential areas also helps to change the face of the urban landscape to match the stature of out country. At the same time, it also helps create job opportunities for many people. Besides, along with the rise of the City’s economy and the growing foreign investment in the market, it opens up a promising prospect for investment in construction of buildings used as offices, high – rise hotels, high – rise apartments … with high quality to meet the increasing living needs of all people. It can be said that the appearance of more and more buildings in the city not only meets the urgent need for infrastructure but also contributes positively to creating a new face for the city.
Ho Chi Minh City University of Technology Socialist Republic of Vietnam Faculty of Civil Engineering Independence – Freedom – Happiness Department of Construction Engineering and Management Department of Structural Engineering HCMC, November 6th, 2020 ASSIGNMENT OF BACHELOR DISSERTATION Student : Nguyen Anh Tu Student ID : 1713839 Class : CC17KCX2 THESIS TOPIC: Minh Thanh Headquarter THESIS OBJECTIVES: a Construction (50%) - Construction site logistics (basement and body) - Procedure of bored pile construction - Modeling of earthwork by PLAXIS to verify the displacement of diaphragm wall and bearing resistance of shoring system by ETABS - Basement construction (Bottom-up solution) - Construction solution for foundation, column, shear wall, beam, slab and cover system - Construction progress - Labor safety b Structure (50%) - Design of typical slab structure (Floor F05) - Design of frame axis (beam, column) and shear wall (axis F03-F04) - Design of structure for earthquake - Design of stair - Design of foundation (bored pile solution) STARTING DATE: 23 – 02 - 2021 FINISHED DATE: 03 – 06 – 2021 INSTRUCTOR: a Construction Engineering & Management Instructor: Ph.D Do Tien Sy b Structural Design & Foundation Design Inst.: Assoc Prof Ho Duc Duy Head of Construction Eng & Management Construction Eng & Management Instructor Le Hoai Long, Ph.D Do Tien Sy, Ph.D Structure and Foundation Design Instructor Ho Duc Duy, Assoc Prof PREFACE My graduation thesis would not have been possible without the assistance of some specific individuals, whom I would like to honor here Firstly, I would like to show my gratitude to my construction instructor, Mr Dr Sy Tien Do, and my structural instructor, Mr Assoc Prof Duy Duc Ho, for their helpful advice and patience, not only in this thesis but also in many other domains of expertise, despite their heavy work schedules From the initial day till the deadline, they have been extremely supportive They have supplied me with a wealth of knowledge and constructive criticism to help me develop every day Without their guidance and support, my thesis would not have been completed Besides, I would like to express my appreciation to Ho Chi Minh City University of Technology (HCMUT) for providing me with the chance to participate in this course, which allows me to use what I have learned in an actual engineering project while also considerably expanding my knowledge in a relevant area I’d also want to show my thankfulness to all of my college who was doing thesis in this semester Finally, forgive me for any error in this humble work and bless my effort with mercy and acceptance And I wish Mr Do and Mr Ho good health and success in their noble career Sincerely Nguyen Anh Tu June 3rd, 2021 TABLE OF CONTENTS PREFACE i TABLE OF CONTENTS ii LIST OF TABLES xv LIST OF FIGURES xxiii NOTATION .xxxi CHAPTER 1: ARCHITECTURAL OVERVIEW 1.1 General Information 1.1.1 Projects Information 1.1.2 Location and characteristics of the construction 1.1.3 Type of construction 1.1.4 Elevation and area of construction 1.1.5 Construction’s position and function 1.2 Architectural Solution 1.2.1 Floor plan solution 1.2.2 Slab components 1.1.1 Cross – section solution 10 1.2.3 Construction traffic solutions 10 1.2.4 Structural solutions of architecture 11 1.2.5 Electrical system .11 1.2.6 Water supply and sewerage .11 1.2.7 Ventilation system .11 1.2.8 Lighting system 12 1.2.9 Fire protection system .12 1.2.10 Lightning protection system 12 1.2.11 Garbage drainage system 12 CHAPTER 2: OVERALL STRUCTURAL SOLUTION 14 2.1 Basic Design Principles 14 2.1.1 Building codes 14 2.1.2 Standard used in frame and slab design .14 2.1.3 Standard used in foundation design 14 2.1.4 Standard design of construction technical measures 15 2.1.5 Calculation Units .15 2.1.6 Software Application Used In Calculation Design 15 2.2 Durability and Grading Design 16 2.2.1 Service requirement 16 2.2.2 Grading design 16 2.2.3 Seismic grade 16 2.3 Structural Solution 16 2.3.1 The distribution of stiffness and mass .16 2.3.2 The distribution of shear walls 17 2.3.3 The distribution of cores 18 2.3.4 Expansion joint, settlement joint, seismic joint 18 2.3.5 Basement 20 2.4 Structural System .20 2.4.1 Structural system on horizontal direction 20 2.4.2 Structural system on vertical direction 22 2.5 Structural Model 22 2.6 Structural Design .24 2.6.1 Requirements for structural design 24 2.6.2 Materials 24 2.6.3 General rules for anchorage and laps length 26 2.6.4 Exposure selection 28 2.6.5 Concrete cover 30 2.6.6 Flexibility 33 CHAPTER 3: LOADS AND ACTIONS .35 3.1 Introduction 35 3.2 Vertical load .35 3.2.1 Permanent load (G) 35 3.2.2 Variable load (Q) .39 3.3 Load combination 44 3.3.1 Load combination for slab design .44 3.3.2 Load combination for frame design 45 CHAPTER 4: DESIGN OF TYPICAL SLAB 47 4.1 Analyze and select structural solution, and layout structural system 47 4.2 Determine the preliminary cross sections for slabs, beams, columns .48 4.3 Determine applied loads 52 4.4 Establish appropriate structural model .53 4.5 Determine bending moment and shear forces(combination) 54 4.6 Design of flexural reinforcement (Section 6.1 EN1992-1-1) 65 4.7 Design of flexural reinforcement by using SAFE 67 4.7.1 General data 67 4.7.2 Procedure 67 4.7.3 Values comparison between EC2 and SAFE .70 4.8 Check the concrete cover (EN 1992-1-1) 73 4.9 Check shear resistance capacity (BS 8110-1997) .73 4.10 Deflection check (EN 1992-1-1) 74 4.11 Check for cracking 76 CHAPTER 5: DYNAMICS ANALYSIS 81 5.1 Wind load 81 5.1.1 Basic wind velocity 81 5.1.2 The roughness coefficient: (Expression 4.4 EN 1991-1-4:2005) 82 5.1.3 The peak velocity pressure (BS EN 1991-1-4: Section 4.5) 83 5.1.4 The force coefficient (Expression 7.9 EN1991-1-4: 2005) 85 5.1.5 The structural factor (EN 1991-1-4 6.3.1(1)) 89 5.1.6 The reasonance response factor (EN1991-1-4 B.2(5)) .90 5.1.7 The peak factor (EN1991-1-4 B.2(3)) 96 5.1.8 Wind load results .97 5.2 Design of structures for earthquakes resistances 104 5.2.1 Basic of design 104 5.2.2 Building regularity in plan 105 5.2.3 Determine the ratio 105 5.2.4 Identification of ground type 105 5.2.5 Identification of level and coefficient of importance .106 5.2.6 Determine ground acceleration 107 5.2.7 Vertical component of the seismic action 108 5.2.8 Determine structural type and behavior 108 5.2.9 Design spectrum for elastic analysis 110 5.3 Top displacement 116 5.4 Story drift .117 CHAPTER 6: DESIGN OF BEAM FRAME – 119 6.1 General data 119 6.1.1 Structural solution and structural system of beam 119 6.2 Design procedure 120 6.2.1 Define bending moment from ETABS 120 6.2.2 Design for flexure (Section 6.2 EN 1992-1-1 122 6.2.3 Design beam reinforcement by using ETABS 125 6.2.4 Check the bending moment resistance 132 6.2.5 Design for shear 133 6.2.6 Deflection check .138 6.2.7 Cracking check 140 6.2.8 Requirement for seismic detailing of beam .141 CHAPTER 7: DESIGN OF COLUMN FRAME – 142 7.1 General data 142 7.1.1 Structural solution and structural system of column frame axis – .142 7.2 Classification of columns .145 7.2.1 Braced and unbraced column 145 7.2.2 Slender and non-slender column .146 7.2.3 Slenderness ratio .146 7.2.4 Effective length of column 146 7.3 Design for flexure 149 7.3.1 Design of slender column 149 7.3.2 Design of short column 152 7.3.3 Summary of column reinforcement 154 7.3.4 Design of column reinforcement by using ETABS 156 7.4 Requirement for links .160 7.4.1 Requirement for seismic detailing of column 162 CHAPTER 8: DESIGN OF SHEAR WALL FRAME – F 163 8.1 General data 163 8.1.1 Structural solution and structural system of shear wall 163 8.2 Flexural design for shear wall 164 8.3 Method of assuming only end zones resist moment .164 8.4 Design procedure 164 8.4.1 Design of flexural 164 8.4.2 Summary of shear wall reinforcement (frame F2-F3) .168 8.4.3 Verify shear resistance of shear wall .169 CHAPTER 9: DESIGN OF TYPICAL STAIR 171 9.1 Introduction 171 9.2 Type of stair 171 9.3 General design considerations 172 9.4 Materials 173 9.5 Preliminary sizing 173 9.6 Actions on structural member 174 9.7 Calculation model of stair 175 9.7.1 Determine moment by hand calculation 176 9.7.2 Determine moment by using SAP2000 177 9.7.3 Design for flexure 180 9.7.4 Deflection check .181 9.7.5 Verify cracking 181 9.8 Calculation of supported beam .182 9.8.1 General data 182 9.8.2 Action on beam .182 9.8.3 Determine bending moment and shear force of support beam 183 9.8.4 Design for flexure 183 9.8.5 Verifying moment resistance 184 9.8.6 Verifying shear resistance 184 9.8.7 Verifying deflection 185 CHAPTER 10: GEOTECHNICAL INVESTIGATION 187 10.1 General data 187 10.2 Calculation method for standard characteristics and design values 187 10.2.1 Division of soil layers 187 10.2.2 Rules for deviation omission 188 10.3 Soil layer classification, description, and distribution character 206 CHAPTER 11: DESIGN OF BORED PILE FOUNDATION 210 11.1 Abstract 210 11.1.1 General 210 11.1.2 Construction procedure 210 11.1.3 Advantages and disadvantages of bored pile 210 11.1.4 Bored pile detail 211 11.2 Pre – design concept .212 11.2.1 Bored pile foundation plan view 212 11.2.2 Materials 212 11.3 Design of bored pile foundation F1(D800) 214 11.3.1 Preliminary dimensions for bored pileF1(D800) 214 11.3.2 Bearing capacity of bored pile F1(D800) 215 1.1.1 Design of foundation F1(D800) 232 1.1.1 Settlement of foundation 241 11.3.3 Design of pile cap 250 11.3.4 Laterally loaded pile 256 11.3.5 Horizontal displacement and surrounding stability of pile 266 11.3.6 Verifying resistance strength of pile 268 11.3.7 Verifying shear resistance of pile 269 11.4 Design of bored pile foundation F6(D800) 270 11.4.1 Preliminary dimensions for bored pile F6(D800) 270 11.4.2 Bearing capacity of bored pile F6(D800) 271 11.4.3 Design of foundation F6(D800) 284 11.4.4 Settlement of foundation .293 11.4.5 Design of pile cap 298 11.4.6 Laterally loaded pile 304 11.4.7 Horizontal displacement and surrounding stability of pile 311 11.4.8 Verifying resistance strength of pile 312 11.4.9 Verifying shear resistance of pile 313 11.5 Design of bored pile foundation F8(D800) 314 11.5.1 Preliminary dimension for bored pile F8 .314 11.5.2 Bearing capacity of bored pile F8(D800) 315 11.5.3 Design of foundation F8(D800) 316 11.5.4 Settlement of foundation .323 11.5.5 Design of pile cap 326 11.5.6 Laterally loaded pile 330 11.5.7 Horizontal displacement and surrounding soil 332 CHAPTER 20: DESIGN OF TYPICAL SLAB FORMWORK Deflection: , OK Limitation: 211.1.1.5 Shore calculation Transferring load area on pile: Load acting on pile: , OK 211.2 Requirement of beam slab reinforcement Beams are installed first, followed by floor reinforcement - Insert structural steel bars on the horizontal beams of the horse seat framework, thread the reinforced bars into levels, and then thread the reinforced center Then, according to the design width, connect the belt to the reinforced heart Retract the horizontal momentum to get the reinforcing down to the beam formwork after the tying is final - Before installing the reinforcement steel in the position, it is necessary to pay attention to placing the statures with the thickness of the thickness of the concrete cover at the necessary positions at the bottom of the formwork CHAPTER 21: DESIGN OF BEAM FORMWORK (FRAME AXIS 2) CHAPTER 212: DESIGN OF BEAM FORMWORK (Frame axis 2) 212.1 General data Beam parameter: Specific weight: CHAPTER 213: Material properties - Sheathing properties: Plywood thickness: Strip width: Moment of inertia: Section modulus: Strength: Elastic modulus: - Joist properties: Type of joist: Moment of inertia: Section modulus: Strength: Shear strength: Elastic modulus: - Stringer properties: Type of stringer: Moment of inertia: Section modulus: Strength: Shear strength: Box steel CHAPTER 21: DESIGN OF BEAM FORMWORK (FRAME AXIS 2) Elastic modulus: - Shore properties: Shores’ diameter: Compressive capacity: [P] = 25 kN Type: Double Stringer spacing: Shore spacing: 213.1.1.1 Applied standard TCVN 4453:1995 TCXDVN 338:2005 CHAPTER 214: Calculation 214.1.1.1 Vertical load Load type Concrete slab self-weight Formwork weight Weight of workers & equipment Load by vibrating Load by pouring concrete Total Symbo l p1 p2 Standard load (kN/m2) 3.125 0.126 p3 p4 p5 2.5 11.75 214.1.1.2 Sheathing calculation Calculating load: Standard load: - Estimation of : n 1.2 1.1 1.3 1.3 1.3 Calculating load (kN/m2) 3.75 0.1386 3.25 2.6 5.2 14.94 CHAPTER 21: DESIGN OF BEAM FORMWORK (FRAME AXIS 2) Figure 21 1: Model of calculation of L1 (Beam) - Chose spacing between joist OK - Bearing capacity: Moment: Stress: , OK - Deflection check: Deflection: OK Limitation: 214.1.1.3 Joist calculation Calculating load: Standard load: Stringer spacing: Figure 21 2: Model of calculation of L2 (Beam) - Bearing capacity: Moment: Stress: , OK CHAPTER 21: DESIGN OF BEAM FORMWORK (FRAME AXIS 2) - Deflection check: Deflection: OK Limitation: 214.1.1.4 Stringer calculation Standard load: Calculated load: Shore spacing: Figure 20 5: Model of calculation of L3 (Slab) - Strength check: Moment: Stress: , OK - Deflection check: Deflection: , OK Limitation: 214.1.1.5 Shore calculation Transferring load area on pile: Load acting on pile: , OK 214.2 Requirement of beam slab reinforcement The requirement of beam slab reinforcement is mentioned in part 20.2 CHAPTER 22: CONSTRUCTION SCHEDULING CHAPTER 215: CONSTRUCTION SCHEDULING 215.1 Purpose and importance of construction scheduling Every project has a construction schedule Not only does the schedule outline how quickly the work will get done, it also outlines how the work will get done The schedule defines the sequence and method in which the materials will be put in place Thus, the earlier the schedule is put on paper (or computer screen, tablet, etc.) and communicated to the project team, the better Here are some benefits of creating a construction schedule before the work begins: - Generating knowledge of the details and fewer surprises will into the project by the need to pre-plan the project - Maximizing quality control measures by properly sequencing the work - Improving planning of resources such as labor and equipment - Enhancing coordination efforts between client and construction operations - Buying-out materials and critical elements with enough lead time - Submitting shop drawings, samples and data sheets in timely fashion - Giving the affected parties such as the subs, vendors, designers and client time to better plan their own activities - Improving safety performance by sequencing the activities to ensure maximum protection for workers - Decreasing risk of damage to adjacent property and installed work leading to a reduced punch list - Pricing winter protection measures accurately by knowing which weather sensitive activities will be put in place during cold weather and the duration of those activities - Achieving the highest level of productivity in order to complete the project in the shortest timeframe reasonably possible CHAPTER 22: CONSTRUCTION SCHEDULING 215.2 Process of construction schedule CHAPTER 216: Content of progress organization - Working order - The relationship that binds the types of work together - Time to complete the project - Determine demand for manpower and resources CHAPTER 217: Procedure of construction scheduling There are steps to make a project scheduling process: Step 1: Plan schedule management Step 2: Define the project activities Step 3: Determine dependencies Step 4: Sequence activities Step 5: Estimate resources Step 6: Estimate durations Step 7: Develop the project schedule Step 8: Monitor and control CHAPTER 218: Considering activities In this thesis, the schedule starts from the construction work of bored pile construction to the finishing of the roof floor There are basic activities: - Install the reinforcement - Install the formwork - Casting concrete - Remove the reinforcement CHAPTER 22: CONSTRUCTION SCHEDULING CHAPTER 219: Quota data To build construction schedule and labor chart, it is needed to design a specific number of labors of each activity Based on “The norm of construction estimation – Construction part” – Official Letter No 10/2019 BXD – VP – Ministry of Construction, as known as “The Norm 10”, student can look over the quota for each activity In this thesis, “Dự toán F1” program will be used to find the norm Note: In term of formwork work, the norms consider the formwork activity includes the production, erection and removing of formwork However, when different starting times Therefore, student take 70% of the quota for installing the formwork and 30% of the quota for removing the formwork The quota code for some typical work is shown in the table below: Formwork norm: Work code AF.81111 AF.89111 Working list Formwork of ice foundation, raft foundation, machine platform Roof formwork, film-coated plywood with skeleton frame, pillar support pillar, height ≤28m Norm 13.61 19.5 AF.81311 Straight wall wood formwork - thickness ≤45 27.78 AF.81132 Column formwork - Square, rectangular columns 31.9 AF.89112 Roof deck formwork, film-coated plywood with skeleton, pillar with pipe spear, height 100m 21.5 Unit 100m 100m 100m 100m 100m Reinforcement norm: Work code AF.61130 AF.61521 AF.61431 AF.61331 AF.61522 AF.61432 AF.61332 AF.61523 AF.61433 AF.61333 Working list Norm Unit Erection of foundation reinforcement, DK> 18mm Roof formwork, film-coated plywood with skeleton frame, pillar support pillar, height ≤28m Straight wall wood formwork - thickness ≤45 Column formwork - Square, rectangular columns Roof deck formwork, film-coated plywood with skeleton, pillar with pipe spear, height 100m Installation of pillar, pillar, DK> 18mm, height ≤28m Erection of rebar wall, DK> 18mm, height ≤28m Installation of reinforcing beams, bracing, DK ≤18mm, height ≤100m Installation of pillar, pillar, DK> 18mm, height ≤100m Erection of rebar wall, DK> 18mm, height ≤100m 5.59 ton ton 9.24 8.01 7.46 9.58 7.79 8.97 10.53 8.57 9.86 ton ton ton ton ton ton ton ton CHAPTER 22: CONSTRUCTION SCHEDULING Concrete norm: Work code AF.21111 AF.21216a AF.22316a AF.32316 AF.22256a AF.32316 AF.22126a AF.22266a AF.32316 AF.22136a AF.22276a Working list Concrete lining foundation, production through batching plant line, pouring with crane, M100, stone 1x2 Concrete foundation, ≤250cm wide, produced through batching plant, poured by crane, M350, stone 2x4 Concrete beams, bracing, roof deck, height ≤6m, SX through batching plant, poured by crane, M350, stone 2x4 Concrete beams, bracing, roof deck, concrete pump, M350, stone 1x2 Concrete column TD>0.1m2, height ≤6m, production through batching plant, poured by crane, M350, stone 2x4 Concrete beams, bracing, roof deck, concrete pump, M350, stone 1x2 Wall concrete - thickness ≤45cm, height ≤28m, production through batching plant, poured by crane, M350, stone 2x4 Concrete column TD>0.1m2, height ≤28m, production through batching plant, poured by crane, M350, stone 2x4 Concrete beams, bracing, roof deck, concrete pump, M350, stone 1x2 Wall concrete - thickness ≤45cm, height ≤75m, SX through batching plant, poured by crane, M350, stone 2x4 Concrete column TD>0.1m2, height ≤75m, production through batching plant line, poured by crane, M350, stone 2x4 CHAPTER 220: Labor calculation Table of labor calculation is illustrated in Annex Norm Unit 0.42 m3 0.58 m3 1.66 m3 1.66 m3 1.98 m3 1.66 m3 2.25 m3 2.33 m3 1.66 m3 2.66 m3 2.75 m3 CHAPTER 23: CONSTRUCTION SAFETY CHAPTER 221: CONSTRUCTION SAFETY 221.1 Safety procedure CHAPTER 222: Equipment operation When mounting equipment, require operators and mechanics to use steps and handholds If the operator's vision is minimal or there is a risk to local staff, use guides or signalpersons When equipment is used in reverse, backup detectors or manuals must be used When working along high-voltage wires, use strict caution and follow all safety regulations If an operator comes into touch with a high-voltage line by mistake, he or she can try to adjust the device sufficiently to sever the connection If the operator is ineffective, he or she can stay on the equipment until the line is deenergized Ensure that computers have the required safety measures and that operators use seat belts where they are available To avoid overturning, exercise caution while running machinery on side slopes When running cranes, be highly cautious not to surpass the operating radius or boom position's protected load limits There are electronic load metrics on the market Enable staff to travel on equipment only if enough seating is available Haul roads must be kept in good working order The state of the road surface (holes, slickness, and excess dust), visibility (curves, barriers, intersections, and dust), and enough distance for cars to navigate are all things to look for (unless one-way) At the end of the day, park the machinery with the brakes engaged, the blade or bowl grounded, and the ignition key disabled The equipment used to clear land must have overhead and rear canopy protection Workers removing vegetation must be shielded from the dangers of irritant and poisonous plants, as well as trained in first-aid care CHAPTER 23: CONSTRUCTION SAFETY When transporting heavy or overweight loads on highways, make sure they are well protected and, if possible, sealed Slow-moving and overweight vehicles are needed to use the required markings and signals to alert oncoming traffic Take proactive steps to ensure the machinery in need of maintenance is not inadvertently turned on When workers must operate under heavy loads backed by wires, jacks, or hydraulic systems, use blocking, cribbing, or other constructive reinforcement Ensure that all guards or protective mechanisms that were missing during equipment maintenance are restored as soon as possible During refueling, switch off engines and not encourage smoke CHAPTER 223: Arrangement of construction layout To avoid overturning, position machinery containing hot or flammable fluids on solid foundations To avoid burns, clearly label high-temperature lines and containers Live steam can be avoided at all costs Fire extinguishers and other required protective devices should be provided Until making big fixes, empty the aggregate bins and batching plants Electrical circuits can be turned off and tagged while electrical machinery is being fixed Make sure wire rope and cable are the right size and weight, that they're wellmaintained, and that they're tested at least once a week CHAPTER 224: Construction of structures Any gaps above ground level should be well guarded For staff on scaffolding or steelwork, have guard posts, safety lines, safety belts, and/or safety nets Ensure the temporary buildings are planned, built, and braced properly When it comes to high-rise concrete construction, extra caution is needed The forms must be sufficiently strong and braced Pouring rates must be kept under or below CHAPTER 23: CONSTRUCTION SAFETY design limits Shoring and reshoring must be well braced and can not be pushed again until the concrete has developed the necessary strength CHAPTER 225: Environment health in construction 225.1.1.1 Noise Construction equipment operators are also using cab enclosures to shield themselves from equipment noise as a result of noise restrictions The use of such enclosures has necessitated better equipment instrumentation, allowing the operator to decide if the system is working correctly without relying on the equipment's vibration While the use of operator enclosures improves the operator climate, it also poses a safety risk since staff outside the enclosures find it difficult to communicate with the equipment operator As a consequence, if injuries are to be prevented, more consideration must be paid to the use of manuals, backup warnings, and hand signals 225.1.1.2 Dust Dust can cause a variety of lung diseases in addition to posing a safety hazard due to a lack of visibility Silica and asbestos dusts are particularly hazardous, causing specific lung diseases (asbestosis and silicosis) Asbestos dust has since been discovered to be a carcinogen 225.1.1.3 Toxic material Construction workers can come into contact with toxic materials by accident at any time, particularly during reconstruction projects Buried utility lines and underground fumes, on the other hand, are the most common dangers During drilling activities, any attempt must be taken to find and secure utility lines When an oxygen shortage or poisonous gas is expected to occur, the air in the work environment should be checked When unfavorable ambient (breathing) conditions are possible, emergency rescue devices such as breathing equipment and lifelines should be available CHAPTER 226: Equipment maintenance 226.1.1.1 Preventive maintenance Preventive maintenance (also known as PM) is a type of maintenance and modification that is performed on machinery on a regular basis to maintain it in the best CHAPTER 23: CONSTRUCTION SAFETY possible working condition It is made up of a variety of elements that can be linked to chain links The abilities of the technician, the manner in which the equipment is used, proper fuel storage, proper equipment lubrication, and accurate periodic adjustment are the main ties in the PM chain If either of the ties in this chain breaks, the machinery will break down prematurely For for piece of equipment, suppliers have established complex lubrication, maintenance, and modification procedures These methods should be followed with caution Major petroleum firms will have recommendations for the best lubricants to use in various working conditions upon request While most construction equipment managers and operators have long relied on manual lubrication with hand-operated or power grease arms, automatic lubrication systems are now available for most products A driven grease pump is attached to the equipment's lubrication (lube) points via 5piping in an automatic lubrication system At intervals calculated by a lubrication control unit that has been previously calibrated for the desired interval, a controlled volume of lubricant is automatically pumped into equipment lube points The following are some of the benefits claimed for automatic lubrication systems: - Increased productivity from elimininating the time lost for manual lubrication - Reduced service labor because manual lubrication is no longer needed - Extended machine component life as a result of optimum lubrication and less oppor- tunity for dirt to enter the machine during servicing - Reduced grease consumption since there is little waste of grease during lubrication Increased safety because mechanics not have to crawl under or over the equipment to perform lubrication 226.1.1.2 Equipment maintenance and repair Although basic maintenance and repair practices are beyond the reach of this section, there is a recent trend in this field that is worth noting Equipment components such as backhoe caps, blade cutting tips, rock drill parts, brake rotors, and engine blocks have been found to last much longer when frozen to a temperature of "300° F ("184° C") The term "deep cryogenic therapy" refers to the freezing procedure Although cryogenic CHAPTER 23: CONSTRUCTION SAFETY treatment raises the cost of treated parts, the increased product life also lowers the total servicing and repair costs of the devices Contractors should conduct experiments to measure the total expense of equipment using treated or untreated materials, including labor and downtime 226.1.1.3 Maintenance organization The supervisor or a service team may perform routine repairs and servicing in the open or in a closed job-site building Unless there are regular harsh weather conditions, servicing is normally done indoors, but service areas can be situated away from haul roads and other sources of dust Operator and crew maintenance programs have both been successfully implemented Many contractors, on the other hand, have seen success with specialist support teams fitted with mobile power lubrication and fueling facilities Repair parts stockage strategies must be carefully formulated based on practice, manufacturer demand, and work requirements, as the availability of repair parts is a common issue at all maintenance stages The stocking and restoration of assemblies and subassemblies by removal often results in a reduction in net operating costs Defective assemblies are withdrawn and restored or replaced with rebuilt assemblies later When computers are available, they can be used to keep track of machinery repairs and costs, as well as to manage spare parts inventory REFERENCES [1] Mohamad Salleh Yassin (2012) Reinforced Concrete Design To Eurocode Universiti Teknologi Malaysia [2] EN 1990 (2002) Eurocode 0: Basic of structural design [3] EN 1991-1-1 (2002) Eurocode 1: Action on structures – Part 1-4: General actions – Density, self-weight, imposed loads for buildings [4] EN 1991-1-4 (2005) Eurocode 1: Actions on structures – Part 1-4: General action – Wind actions [5] EN 1992-1 (2004) Eurocode 2: Design of concrete structures – Part 1-1: General rules and rules for buildings [6] EN 1997-1 (2004) Eurocode 7: Geotechnical design – Part 1: General rules [7] EN 1998-1 (2004) Eurocode 8: Design of structure for earthquake resistance [8] Võ Bá Tầm (2013) Nhà cao tầng bê tông – cốt thép [9] TCVN 4453-1995 Monlithic concrete and reinforced concrete structures Codes for construction, check and acceptance [10] TCVN 338-2005 Steel structure – Design standard [11] Nguyen Ngoc Anh Tram (2020) Graduation thesis: Office of the party city committee HCMC University of Technology [12] Hoang Vu Duy (2020) Graduation thesis: Five stars tower HCMC University of Technology