HIGH-RISE BUILDING- FORM WORK essential for efficiently shaping and supporting concrete structures during construction
- 1. HIGH RISE BUILDINGS AND THEIR FORMWORK MMBC - VIII
- 2. INTRODUCTION AND DEFINITION • Emporis standards- “A multi- story structure between 35-100 m tall or a building of unknown height from 12 – 39 floors is termed as high rise” • The international conference on fire safety- “Any structure where the height can have a serious impact on evacuation” • Building code of Hyderabad, India – “A high rise building is one with 4 floors or more or 150 m or more in height” • Massachusetts, United States general laws – “A high rise is being higher than 70 feet (21 m)”
- 3. DESIGN CONSIDERATIONS • There are 3 major factors to consider in the design of all structures -Strength -Rigidity -Stability • As height increase, the rigidity and stability requirements become more important, and they are often the dominant factors in the design. So, - The size of the members may be increased above and beyond the strength requirements - Change the form of the structure into something more rigid and stable to confine the deformation and increase stability -P - ∆ effect, In which the eccentricity of the gravity load increases to such a magnitude that it brings about the collapse of the columns as a result of axial loads - Therefore, an important stability criterion is to assure that predicted wind loads should be below the load corresponding to the stability limit - The second consideration is to limit the lateral deflection to a level that will ensure that architectural finishes and partitions are not damaged Variation of wind velocity with height Rigid structure to increase stability
- 4. FORMWORK FOR HIGHRISE BUILDINGS • The selection of formwork systems in high-rise buildings is often governed by their competence in optimizing concrete activities in an isolated manner, without relating this choice to the entire construction workflow. • Advanced high-rise formwork technologies have an upper hand over the regular ones. • The importance of advanced high-rise formwork systems in streamlining the workflow of concrete and other downstream activities allows for a better high rise structure allowing for better resource allocation. • Additionally, there is more waste reduction, smaller work batches, less inventory, and safer working environment.
- 5. FORMWORK SELECTION PARAMETERS Internal Parameters External Parameters Geometry Repetitive Simple / complex Changing geometry Space Constraint of existing road or building Storage area Assembly area Concrete Rate of pouring/ concrete pressure Concrete Finish Curing time Wind Wind load Sequence of work Cycle time Crane Capacity Availability Type Boom reach Formwork choice Existing formwork material to be reused Rental or purchase Best value for current project v/s Flexibility for future projects Safety Special requirements needed Construction Planning Milestone Working schedule/shifts Project duration Holidays Local rules and regulations PermitsRestricted Noise Safety requirements Construction of high-rise buildings requires innovative formwork system technologies to overcome the limitations of space, budget, and time. However, many parameters affect the choice of formwork systems and are mainly divided into internal and external parameters as shown below.
- 6. TYPES OF FORMWORK 1. SLIP FORMWORK •Slip formwork is a construction method in which concrete is poured into a continuosly moving form •Basically, this method involves the continuous placing of concrete in a shallow mould having the same plan as the building to be constructed. •This rigid mould or slip form forms the working deck which is jacked slowly upwards at a controlled rate until the required elevation is reached •Method of vertically extruding a reinforced concrete section and is suitable for construction of core walls in high ride structures, lift shafts, stair shafts, towers •The formwork rises continuously at a rate of about 300 mm per hour, supporting itself on the core and not relying on support or access from other parts of the building or permanent works •Allows for continuous pouring of concrete into walls of a structure and only stops when the full required height of the structure has been reached •The height of the formwork is designed in such a way that while the top of the formwork is being filled by concrete the lowest layer of concrete poured earlier has already gained an initial set •When the formwork is moved upwards the concrete that is then exposed remains firm. Slip Formwork
- 7. 2. JUMP FORMWORK •Generally the jump form systems comprises the formwork and working platforms for cleaning/fixing of the formwork, steel fixing and concreting •Jump form, often described as climbing form, it is suitable for construction of multi – floor vertical concrete elements in high – rise structures such as shear walls, core walls , lift shafts, stair shafts and bridge pylons •It is highly productive system designed to increase speed and efficiency while minimizing labor and time 3. CLIMB FORM CONSTRUCTION •It is a special type formwork for vertical concrete structures that rises with the building process. •It is economical, rapid and accurate method of constructing reinforced concrete or post tensioned concrete structures •At its most basic level, climb forming is a type of movable formwork which is slowly raised, allowing continuous extrusion of concrete •Effective solution for buildings that are either very repetitive in form (such as towers or skyscrapers) or that require a seamless wall structure Jump Formwork Climb form construction
- 8. 4. TABLE FORM/ FLYING FORM WORK •A table form work is a large pre – assembled formwork and falsework unit, often forming a complete bay of suspended floor slab •It offers mobility and quick installation for construction projects with regular plan layouts or long repetitive structures so it is highly suitable for flat slab and beam layouts •It is routinely used for residential, hotels, hostels, offices and commercial buildings 5. SYSTEM COLUMN FORMWORK •The column formwork systems now available are normally modular in nature and allow assembly and erection on site while minimizing labor and crane time •They are available in steel. Aluminum and even cardboard (not reusable but recyclable) and have a variety of internal face surfaces depending on the concrete finish required •Innovations have led to adjustable, reusable column form which can be clamped on site to give different column size 6. TUNNEL FORMWORK •Tunnel formwork is used to form repetitive cellular structures and is widely recognized as a modern innovation that enables that construction of horizontal and vertical elements together •Significant productivity benefits have been achieved by using tunnel form to construct cellular buildings such as hotels, low and high rise housing, hostels, student accommodation, prison and barracks accommodation TABLE/ FLYING FORMWORK SYSTEM COLUMN FORMWORK TUNNEL FORMWORK
- 9. ISSUES 1. FUNDS - Cost is a major factor. 2. LOCAL RULES AND REGULATIONS - Planning permission, often there will be certain rules to comply to when using a certain amour of space 3. PLANNING One of the biggest problems in construction of a skyscraper is planning. To construct a small house you need a progress schedule. To build a skyscraper you need a critical path schedule. Usually a tall building is built in a high density area and street traffic has to be taken into consideration for delivery of materials and erection of scaffolding and cranes. 4 .LIGHTING - Shadows can cast over other buildings and mess with light levels. 5. MATERIAL USED - Materials being Able to take certain strains 6. DESIGN FOR LATERAL FORCES With really high buildings the wind and temperature becomes a major factor, and the building needs to accommodate for the sway and stretch of the skyscraper. 7. AXIAL SHORTENING OF VERTICAL MEMBERS In a tall building, you'll have the issues of axial shortening (from elastic deformation and creep) which could introduce additional P-Delta effects to design against and affect the centre of gravity of the building. To address this, you'd have to have a look at the construction program and ensure that the shortening effects in columns/walls are relatively equal across the board. 8. Load bearing capacity of the soil. 9. Social, cultural, political, and historic issues. 10. Availability of labor and resources. 11. Risk of earthquakes and extreme weather.
- 10. MATERIALS REQUIREMENTS •In general, for high rise buildings the resistance to overturning moment and lateral deflection will almost always require additional material over and above that required gravity load alone •The material required for floor framing is a function of the column to column span and not building height •However the material required for the vertical system, such as columns and walls in high rise structures is substantially more than that of low rise building •The material increases in the ration (n + 1)/2, where n is the number of floors, because the vertical components carrying the gravity loads will need to be strengthened for full height of the building , requiring more vertical steel than a one – storey structure having the same floor area TYPES •The structural materials used in high-rise buildings are typically one or a combination of (reinforced or pre-stressed) concrete, structural steel and composite systems. •Structural material systems for high-rise buildings should be chosen by carefully considering architectural, economical and site factors. The economic drivers vary by geography as the relative costs of material, labour, time and space vary from one location to another. •Other factors to consider in choosing the structural material include: local market preference/availability; project size/height; building form (regular vs complex); design considerations (fire performance, dynamic performance, adaptability, and the like); site location/access; and speed of construction.
- 11. CONCLUSION • The spurt in high-rise projects around the country has been instrumental in giving the much needed fillip to climbing formwork systems. • With a perceptible shift in buyer behaviour, contractors today have today become aware that the significant cost and time saving accrued due to the use of formwork systems; can help offset the perceived high initial capital, in a rather quick period of time. • Rental companies too have taken a clue from the market trends and are today incorporating formwork as part of their product portfolio in increasing numbers. • With newer high-rise projects being launched, almost every alternate day, the market for formwork systems, is expected to quite literally, touch dizzy heights in the next few years. SOURCE : https://www.quora.com/What-is-the-major-problem-faced-and-presented-to-constructing-skyscrapers-that-non-high-rise -buildings-do-not-face-in-their-constructions https://www.slideshare.net/aks254447/highrise-structural-systems https://www.slideshare.net/MSulmanSarwar/highrise-buildings-43531318 https://www.slideshare.net/ctm2015vnit/high-rise-building-construction
- 13. CASE STUDY 1 - MIVAN TECHNOLOGY MIVAN TECHNOLOGY It is a precision-engineered formwork fabricated in Aluminium and how the uses of mivan, can save time and money for a multi-crore project. INTRODUCTION The most effective means available for the construction of high, medium and low rise mass housing R/C structures. It is a precision-engineered formwork fabricated in Aluminium, monolithic pouring. Walls, columns, slabs & beam are poured together. It is flexible in design and can form any architectural or structural configuration, such as stairs, bay windows, curved features, etc. Mivan Shuttering Mivan shuttering concrete pouring
- 14. WORKING OF MIVAN Step 1: Detail Drawing of Mock up Shuttering. Make sure the building architectural &structural details shall be freeze before fabrication of Aluminium Shuttering. It could be cumbersome while executing the works if there is any revision in drawing The plan of Tower E building Step 2: After surveyor provides marking on columns then reinforcement of columns work start after that fixing of mivan shuttering on column is done. The fixing of mivan plate on column. Step 3: Fixing of Slab Panels after erection of vertical wall panels then reinforcement of beams, slab and conduting work is done. The complete work of reinforcement of beam, slab, mivan shuttering of slab panels and conduting works. Step 4: We can start concreting work after slab shuttering & conduting work is done. The concreting work of column, beams and slab.
- 15. FEATURES OF MIVAN FORMWORK 4. Striking time •Vertical (Wall) Formwork – 12 hours after concreting or when concrete strength has reached 2N/mm2. •Horizontal (Deck) Formwork – 36 hours after concreting or when concrete strength has reached 10N/mm2. 5. Pouring System •Monolithic pouring for: Slabs Walls Columns Beams 6. Durability •The panels are made out of Structural Grade Aluminium alloy. •Around 200 repetitions can be achieved while using Aluminium Formwork System. 1. Sheet Thickness & Panel Sizes •The concrete face of panels (Al Sheet) is 4 mm thick. •Standard sizes of Panels are: 2000x600,2000x300,1200x300,850x300. •Apart from above any size as required shall be manufactured and delivered. 2. Load Carrying Capacity •High load carrying capacity of 7-8 Tonnes Per square meter Weight •Light weight is the main advantage over conventional formwork technology. •Aluminium formwork weighs around 18-20 kg per meter square. 3. Cycle Time •High speed of construction can be achieved by this system that means faster completion of project. •7 Days per floor.
- 16. BEAM COMPONENTS Prop Head Beam Side Panel Beam Soffit Bulkhead Beam Soffit Panel DECK COMPONENTS Prop Length Deck Panel Deck Mid –Beam Soffit Length Deck Prop
- 17. OTHER COMPONENTS External Corner Internal Corner Internal Soffit Corner External Soffit Corner WALL COMPONENTS Wall Panel Kicker Rocke r
- 19. CONCLUSION Concrete construction has gone through significant changes since the early 1990s and continues to develop innovation in formwork. Some of the pioneering companies in modern form working system are peri, doca system, outinord, meva, acrow. We thus infer that mivan formwork construction is able to provide high quality construction at unbelievable speed at reasonable cost. This mivan technology has great potential for application in India to provide affordable housing to its rising population.