BUILDING CONSTRUCTION REPORTName : Rohit A.DigraCollege: Dr.Baliram Hiray College Of ArchitectureYear : 5th Year B.Arch (I.D.)

LIFTS AND ESCALATORS

LIFTS AND ESCALATORS

LiftThe smartness of any vertical system depends upon the intelligence with which it handles the traffic. The transportation capacity of any elevator system depends upon the critical period of maximum demand and the system must serve the calls during the period of maximum demand while simultaneously subjecting passengers to an acceptable waiting period of time.The no. of elevators and the locations in a particular building depends upon various factors like flow of traffic, building population, quality and quantity of services expected.

Hc = 300p/t ---hc-handling capacity of car, t—round trip time, per persons/car.

N=vi/300p=v/hc,v—peak hr. trafficLift/elevator an appliance by which persons and goods are moved vertically from one level to another; its component part consists of the winding machine, car, counterweight, guides, suspension ropes, control gear with safety devices.

LIFTS AND ESCALATORS

Passenger elevatorStructural slab of machinery, 150 mm thk. Designed to sustain min. 1000kg/m2udl.Power supply 400volts, 3phase,4wires & 230 volts 1phase. All hoist way walls should be minimum 230mm brick or 150mm r.c.c.Centre opening door should be preferred.Depth should be 1.40m (4’6”) below the lowest landing lvl.Lift pit on hard strata---raft foundation-completely water tight, m.s. Ladder to be provided

Provide 40cmx40cmx75cm,1:2:4 concrete blocks in lift pit for buffer spring.Rcc bracer beams to be provided in bk. Masonry & guide rails should be fixed to it.4 no. Pockets to be provided in machine room slab as fixing supports.Specifications to be confirmed with elevator agency.

LIFTS AND ESCALATORS

Grouping of elevators----minimize walking distance between entrances, quick access to cars, less confusion between waiting passengers.

Escalator

An escalator is a conveyor transport device for transporting people, consisting of individual, linked steps that move up or down on tracks, which keep the treads horizontal.As a power-driven, continuous moving stairway designed to transport passengers up and down vertical distances, escalators are used around the world to move pedestrian traffic in places where elevators would be impractical. Principal areas of usage include department stores, shopping malls, airports, transit systems, convention centers, hotels, and public buildings.

The benefits of escalators are many. They have the capacity to move large numbers of people, and they can be placed in the same physical space as one might install a staircase. They have no waiting interval (except during very heavy traffic), they can be used to guide people toward main exits or special exhibits, and they may be weatherproofed for outdoor use.Electric traction elevators are used in exclusively in tall buildings.Hydraulic elevators are used generally in low rise freight service which rises up to about six storey’s & also for low rise passenger service.Escalator’s to be viewed as preferred transportation system whenever heavy traffic volumes are expected between relatively few floors.—AIRPORT TERMINALS, SHOPPING malls, etc.Escalators used when it is necessary to move large no. Of people from floor to floor.

These stairs have continuous operation without the need for operators.Minimum depth of tread-indirection of travel –400mmMaximum rise between treads –230mmMinimum width of tread -- 600mmMaximum width of tread –1000mmMaximum clearance bet. Tread & adjacent skirt panel Maximum distance bet. Handrail centrelines—758mm(min)Width of escalator---1140mm

StepsHand Rail

Truss

Driving Machine

Endless Belt

SHELLS

A shell structure is a thin, curved membrane of slab, usually of reinforced concrete, that functions both as structure and covering, the structure deriving its strength and rigidity from the curved shell form.   It is generally capable of transmitting load in more than two directions to supports. These structures are highly efficient structurally when they are so shaped, proportioned and supported that they transmit the loads without bending or twisting. A shell is defined by its middle surface halfway between it’s inner surface and outer surface. Depending upon the geometry of the middle surface, shells may be classified as: •A Dome•A barrel arch•Cone, and•Hyperbolic and parabolic

  A thin shell has relatively small shell compared to other dimensions. It should not be so thin that the deformation would be large compared with the thickness. The shell shearing stresses normal to the middle surface should be negligible. The thin shells usually are design so that normal shears, bending moments and torsions are very small except for relatively small portions.   The term shell is used to describe these structures by reference to the very considerable strength and rigidity of thin, natural, curved forms such as the shell of an egg, a nut and crustaceans such as the tortoise. The strength and rigidity of curved shell structure makes it possible to construct single curved barrel vaults 60 mm thick and double curved hyperbolic paraboloids 40 mm thick in reinforced concrete for spans of 30.0.

SHELL STRUCTURES

SHELLS

Single curvature shells, curved on one linear axis, are part of a cylinder or cone in the form of barrel vaults and conoid shells. Double curvature shells are either part of as sphere, as a dome, or a hyperboloid.

The term single curvature and double curvature are used to differentiate the comparative rigidity of the two forms and the complexity of the centering necessary to construct the shells forms. Double curvature of a shell adds considerably to its stiffness, resistance to deformation under load and reduction in the need for restrain against deformation.

  The most straightforward shell construction is the barrel vault, which is part of a cylinder or barrel with the same curvature along its length. The short span barrel vault is used for the width of the arch ribs between which the barrel vaults span. It is cast on similar arch ribs supporting straight timber or metal centering which is comparatively simple and economic to erect and which can, without waste be taken down and use again for similar vaults.

A shell structure is many times more expensive than a portal frame structure covering the same floor area because of the considerable labor require to construct the centering on which the shell is cast.

The material most suited to the construction of a shell structure is concrete which is a highly a plastic material when first mixed with water that can take up any shape on centering or insert formwork.

SHELLS

SHELLS

Domes  Domes are semi-spherical or semi-elliptical in shape. They are used as roof structures. Constructed of stone or bricks or concretes. They are supported on circular or regular polygon shaped walls.   Dome structures have within certain height and diameters vary small thickness. Dome structures are generally used in monumental works were roof are to be build on building circular or hexagonal in plan.   The domes can be either (1) Smooth shaped domes (2) Ribbed domes.   Smooth shell domes can have either shell of uniform thickness or with shell of uniformly varying thickness. A dome can be constructed with or without lantern.   Space frame dome exceptionally light structures, which permit the spanning of large distances with relative reduction materials. The dome surface can be subdivided into a number of triangles or other regular polygons the sides of which are hinge bars. Any dome shell roof will tend to flatten due to the loading and this tendency must be resisted by stiffening beams or similar to all the cut edges. As a general grid domes which rise in access of 1- 6 of their diameter required a ring beam. Timber domes like their steel counter parts are usually constructed in a single layer grid system and covered with a suitable thin skin membrane.

SHELLS

Conoid Shells These are similar to barrel vaults but are double curvature shells as opposed to the singlecurvature of the barrel vaults. Two basic geometrical forms are encountered.  A straight line is moved along a curved line at one end and a straight line at the other end. The resultant shape being cut to the required length.A straight line will move along the curve line at one end and the different curve line at the other end.  

SHELLS

Barrel Vaults

These are shells of single curvature and are commonly called barrel vault. Geometrically a barrel wall is a cut half cylinder which presents no particular setting out problems. When two barrel walls intersect the lines, lines of intersection are called groins. Barrel walls like domes tend to flatten unless adequately restrained and in vault restraint will be required art the ends in the form of a diaphragm and along the edges.

From a design point of view barrel vaults act as a beam with the length being considered as the span which if it is longer than its width or chord distance is called a long span barrel vault, or conversely if the span is shorter than the cord distance is termed short barrel vault. Short barrel vaults with their relatively large chord distance and consequently large radii to their inner and outer curved surfaces may require stiffening ribs to overcome the tendency to buckle. The extra stresses caused by the introduction this stiffener or ribs will necessitate the inclusion of extra reinforcement at the rib position, alternatively the shell could be thicken locally about the rib for the distance of about 1/5th of the rib spacing.

The concrete shell is from 55-75 thickness for span of 12.0-30.0 respectively. This thickness of concrete provides sufficient cover of concrete to protect the reinforcement against damage by fire and protection against corrosion. The wet concrete is spread over the centering on the reinforcement and compacted by, hand to the required thickness.

SHELLS

The usual form of barrel vaults is the span vault where the strength and stiffness of shell lines at right angles to the curvature so that the span is longitudinal to the curvature. The usual span of a long-span barrel vault is from 12.0-30.0 mts. with the width being about half the span and the rise about one fifth of the width. To cover large areas, multi-span, multi-bay barrel vault roofs can be used where the roof is extended across the width of the vaults as a multi-bay roof, as a multi-bay, multi-span roof.

Edge and valley beam Due to the self-weight and imposed loads the thin shell will tend to spread and its curvature flatten out. To resist this, reinforced concrete edge beams are cast between columns as an integral part of the shell. Edge beam may be cast as a drop beam or upstand beam or partly dropped beams. 

SHELLS

Expansion joints

If there is excessive contraction or expansion the stresses so caused might deform the shell and cause gradual collapse. To limit contraction or expansion, continuous expansion is formed at interval of about 30 mts. Both along the span and across width of multi bay, multi span barrel vault roofs. The expansion joint transverse to the span of the vaults is formed with a non-ferrous flashing to weather. Longitudinal expansion joints are formed in a valley with upstand weathered with non-ferrous capping over the joint.

 

SHELLS

 North light reinforced concrete barrel vault  To avoid the possibility of overheating and glare from top light in the summer a system of north light reinforced concrete barrel vault is used. The roof consist of a thin reinforced concrete shell on the south facing side of the roof with a reinforced concrete framed north facing slope, pitched at 60-80 degree. Rigidity of barrel vault depends on its continuous curvature, which in this type of roof is interrupted by north light opening. North light shell is less efficient structurally than a barrel vault shell. The economic span of the north light shell is 12 – 15 Mts. as compared to 30 or more of barrel vault.

SHELLS

SHELLS

Hyperbolic Paraboloids These are obtained by sliding a vertical parabola with upward curvature on another parabola with downward curvature in a plane at right angle to the plane the first. Here directions, up in one and down in the other. This surface generally called a saddle surface. There are different ways in which saddle surfaces can be supported. The surfaces are generally design with small rises so as to produce fairly flat roofs. If cut by planes parallel to the two parabolas, the edges will be parabolic and the supporting structure must be parabolic. 

To obtain a more practical shaped than the true saddle the usual shaped hyperbolic paraboloid which is formed by rising of or lowering one or more corners of a square. By virtue of its shape this form of shell roof has a greater resistant to buckling than dome shapes. Hyperbolic paraboloid shells can be used singly or conjunction with one another to cover any particular plan shape or size. If the rise is small the result will be the hyperbolic paraboloid of low curvature acting structurally like a plate which will have to be relatively thick to provide the necessary resistance to deflection. To obtain full advantage of the inbuilt strength of the shape the rise to diagonal span ratio should not be less than 1:15 indeed the higher the rise the greater will be the strength and the shell can be thinner. 

SHELLS

SPACEFRAME

SPACEFRAME

SPACEFRAMEA space frame or space structure is a truss-like, lightweight rigid structure constructed from interlocking struts in a geometric pattern. Space frames usually utilize a multidirectional span, and are often used to accomplish long spans with few supports. They derive their strength from the inherent rigidity of the triangular frame; flexing loads (bending moments) are transmitted as tension and compression loads along the length of each strut.Most often their geometry is based on platonic solids. The simplest form is a horizontal slab of interlocking square pyramids built from aluminium or tubular steel struts. In many ways this looks like the horizontal jib of a tower crane repeated many times to make it wider. A stronger purer form is composed of interlocking tetrahedral pyramids in which all the struts have unit length. More technically this is referred to as an isotropic vector matrix or in a single unit width an octet truss. More complex variations change the lengths of the struts to curve the overall structure or may incorporate other geometrical shapes.Space frames were independently developed by Alexander Graham Bell around 1900 and Buckminster Fuller in the 1950s. Bell's interest was primarily in using them to make rigid frames for nautical and aeronautical engineering although few if any were realised. Buckminster Fuller's focus was architectural structures and has had more lasting influence.

SPACEFRAMESpace frames are an increasingly common architectural technique especially for large roof spans in modernist commercial and industrial buildings.

ADVANTAGES OF SPACE-FRAMES:Space frame systems are three-dimensional structures which are constructed by connecting straight tubular struts to each others with the use of solid spherical hubs. Theese systems carry loads by axial forces. The conic parts are welded to the strut edges and the struts connecting by spherical hubs.Some of the advantages of space frames are described below:•Because of the space frame systems are three-dimensional structures which work in two direction, for a large spans it provides economical solutions.•İt is possible to cover spans until 100 m. without column by using space frame systems.•They provide a great flexibility in the selection of support locations and allows to apply for different geometrical shapes / areas.•The design / manufacture / installation process is completed in a very short interval due to the use of prefabricated components. İt gives a big opportunity to the customer to start his production•Transporting to far distances is provided easily due to the use of prefabricated components.•Space frame systems are lighter than traditional steel and reinforced concrete structures. Therefore, it provides significant economy in foundation costs.•Space frame systems are the most useful structures for the earth-quake areas due to their light unit weight.•İt is not nacessary to cover by hung ceilings because of its aesthetic appearance.•Additional structures to support the heating, ventilating, electrical and other systems are not required for space frame structures.•Because of the aesthetic attribute, space frames are very suitable for glass or policarbonate skylights.•İt provides various alternative solutions in architectural areas for complex geometrical shapes (pyramid, triangle, dome, barrel vault e.t.c.)

SPACEFRAME