Southern Cross Station, Melbourne Australia

Posted by HB on Tuesday, November 23, 2010 , under | comments (1)



Southern Cross Station

Architect : Grimshaw Jackson JV         

Structural Engineer : Winward Structures

Services Engineers: Lincolne Scott Australia

 

 

A   roof of shimmering zinc-coated aluminium billows across the platforms of Southern Cross Station in central Melbourne. The station is part of an AS$350 Million redevelopment which unites the rail and bus terminals and was completed in time for the 2006 Commonwealth Games. The surrounding urban landscape has been reconfigured so the station acts as a link rather than a barrier between the central business district and the docklands.

 

 

Southern Cross Station

 

The   undulating profile is designed to remove diesel fumes without the need for a costly mechanical system. Ventilation lanterns at the top of each dome allow the wind to draw out fumes by Venturi effect. Heat build up under a single skin metal roof would cause disturbance to the air flow, so an inner lining of faceted 200 mm thick triangular panels has been installed between the steel bracing to effectively insulate the roof. Air is drawn up through gaps between the ceiling panels into a void between the inner and outer layers.

 

 

Southern Cross Station

 

Southern Cross Station

 

The   outer roof skin is curved in two directions using tapered strips of zinc-coated aluminium. Equipment was brought from Germany to roll the strip metal on site. To achieve the tight curves the strips were passed through the rollers four times in batches of fi ve or ten strips, each batch with a slightly different tapered profile. This complex process was only possible because the roofing sub-contractor was appointed at the detailed design stage to develop fabrication details alongside the architects, a process Grimshaws say worked remarkably well.

 

 

Southern Cross Station

 

The   main structure is steel. Curved roof arches span up to 40 meters between trusses that are in turn supported on concrete  filled steel columns. The long spans reduce the number of columns required allowing for future flexibility or re-arrangement of the platforms beneath. 900 mm wide gutters either side double as maintenance walkways. Above the trusses 20 meter long ETFE pillows provide natural light on the platforms. The ETFE is fritted to reduce heat gain from the summer sun bathing the platforms in a cool forest floor light.

 

Southern Cross Station

 

Drawing labels :

 

 

 

North South Section

 

1.     Typical column    

 

10  mm thick circular mild steel (MS) column casing bolted down to concrete plinth. Casing tapers from 2000  mm diameter at base to 1180  mm at top. Height varies from 6 m to 12 m. Casing filled with concrete by pressure pumping from base once bolted in place.

 

Level 1 Plan Level 1 Plan – 1:500

 

 

2.     Wishbone column arms

 

Tapered arms made from varying thickness steel plates welded at edges with internal 6 mm thick diaphragm stiffening plates at 1250  mm centres.  1000 mm diameter 16 mm thick circular hollow section (CHS) welded through base of arm for connection to column. CHS connector located in column head and welded in place prior to filling column with concrete.

 

3.     Spine truss

 

Steel truss brought to site in prefabricated 4-bay sections. 356 mm diameter curved top and bottom chords. 356 mm diameter curved top horizontal member. 273 mm diameter vertical members. 219 mm diameter horizontal diagonal braces. 168 mm diameter diagonal braces either side of column connection. Three pin connections on truss prefabricated and site welded to each column arm.

 

4.     Roof steelwork

 

356 mm diameter MS primary roof arches curved to form undulating roof profile. 168 mm diameter MS lateral struts bolted to cleats welded to arches. 168 mm diameter MS diagonal braces bolted to 356 mm diameter bosses welded to arches. 76 mm diameter MS posts with brackets to support roof panels and cladding rails welded to primary arches at maximum 1500 mm centres.

 

5.     Ceiling panels

 

200 mm thick prefabricated triangular panels bolted between diagonal braces to cleats on MS posts. Panel frame made from 150 x 75 mm galvanised light gauge steel channel sections. Profiled galvanised steel top sheet. Joints between panels covered with reinforced plastic strips. 1.5 mm thick polyester powder coated aluminium panels to underside to form finished ceiling. 100 mm gaps between ceiling panels above truss chords and primary arch to allow fumes to be drawn into roof void. Bird mesh fixed to rear of ceiling panels over gaps.

 

6.     Cladding support rails

 

114 mm diameter curved aluminium rails bolted to MS posts to support roof cladding.    

 

7.     Roof cladding 

 

Tapered 1 mm gauge zinc-coated aluminium standing seam roof cladding clipped over proprietary supports. Continuous void between roof cladding and ceiling panels to allow fumes to be drawn up to ventilation domes at tops of arches.

 

 

natural ventilation via roof cowls

Diagram showing natural ventilation via roof cowls

 

 

8.     Gutter

 

200 75 mm parallel flange channel (PFC) and 200 x 200 mm universal column (UC) gutter frame bolted to steelwork at each primary arch. 930 mm width 20 mm plywood gutter base bolted to steel frame. Non-slip single ply membrane gutter lining to act as maintenance walkway. 4000 x 700 x 220 mm deep sump with two outlets at each column position. Folded 2 mm aluminium vertical cladding to conceal gutter below rooflight. Two 125 mm diameter rainwater downpipes running down each column arm and cast into concrete trunk of column. One electrical conduit in each column arm running up into ceiling void.

 

 

Typical Gutter  

Typical Gutter Section – 1:40

 

9.     Rooflights

 

20 metre long ETFE pillows running along full length of roof over spine trusses with 18 mm diameter white frit over 60% of surface. Extruded aluminium perimeter clamp plate bolted to UC gutter structure. Clamps at ends of ETFE pillows made from back-to-back angles to form expansion joint.

 

 

Cut-away view of typical column, truss, rooflight and roof

Cut-away view of typical column, truss, rooflight and roof

 

 

 

Southern Cross Station

Jovanovich House

Posted by HB on Sunday, November 21, 2010 , under | comments (1)



Jovanovich House

Lorcan O’Herlihy Architects has mastered the art of building on steep or confined sites and its houses respond creatively  to the topography and the urban context. Most recently, the southern California firm transformed a hermetic A-frame house perched  on the edge of a canyon by making modest additions, opening up the interiors to decks and sweeping views, and wrapping the hybrid  form in a white scrim. The crisp cut-out carapace sits lightly on the street and from below it appears as insubstantial as a kite, floating free  of the wooded slope.

 

To accommodate a young family and their guests and to take advantage of a 180° view, the architects gutted the existing shell, enclosed the carport to serve as a spacious foyer, and cantilevered  a garage and guest suite out to the south. The new rooms add only 80m2 to the existing 340m2 of enclosed space, but the decks furnish another 200m2. ‘We took the old structure as a found object to be cut away and opened up,’ says Lorcan O’Herlihy. ‘The task of infusing a banal house with energy and light was harder than starting from scratch, but the cost of building anew on such a  site would have been prohibitive.

 

would have been prohibitive.’The big move was to unify old and new with PVC-coated polyester woven yarn, stretched taut on a lightweight metal frame. The mesh  is cut away to frame views out and  up to the sky. It conceals and reveals, provides shade and thermal protection, and adds depth to the composition. The layering and articulation of the facades echoes that of the practice’s Formosa condominiums in West Hollywood, which assert their urbanity as a metallic sculpture in fire-engine  red.  These facades are also inspired by art works – O’Herlihy is an accomplished painter who created his own tower house in Venice as  a three-dimensional version of his geometric abstracts (AR January 2004). Here, on a quiet residential street, the effect has to be subtler  and softer. ‘We chose the fabric, which should last five years, in preference to perforated metal, because it is light, ephemeral  and tactile,’ says O’Herlihy.

 

The house exploits the shifts of level on the site. An inclined bank leads to the entry foyer, from where a crisp steel stair descends to the living room. A long hallway along the west front links the open kitchen to the double-height living room, media room and guest room. Pocketing glass sliders open onto a broad wooden deck that runs the length of the house. Bleachers and steps descend to a pool and garden down the slope. The decks extend the house into the landscape and reveal the drama of the guest suite to the rear of the garage, which is supported on a tree-like structure of steel tubes. Within, stairs lead up to an all-white master suite, infused with natural light, that opens onto roof decks. From this lofty perch, you feel as though you are floating above the expanse of trees and the blue blur of the ocean.

 

Jovanovich House Wrapped in a gauzy fabric veil, the house clings precipitously to the hillside

 

 

Jovanovich House remodelled house exploits light  and views

 

 

Jovanovich House Cross Section

the mesh conceals and reveals, provides shade  and protection,

and adds depth to the composition

 

 

Jovanovich House

The mesh is cut and shaped around the original structure

 

 

Jovanovich House

The master bedroom, with  LA panorama

 

 

Jovanovich House Floor Plans

Upper and lower floor plans

Architectural Design In Steel # Frame design

Posted by HB on Thursday, November 11, 2010 , under | comments (1)



Portal-frame structure created usingcellular beams

 

1. The frame as the basic unit of construction

 

A framework is a three-dimensional assembly of steel members that form a self-supporting structure or enclosure. The most common and economic way to enclose a space is to use a series of two-dimensional frames that are spaced at equal intervals along one axis of the building, as shown in Figure 1(a). Stability is achieved in the two directions by the use of rigid framing, diagonal bracing, or through the supporting action of concrete shear walls or cores. This method of ‘extruding’ a building volume is equally applicable to any frame geometry, whether of single or multiple bays.

 

Three-dimensional frames can vary enormously in overall form,in the overall geometry of the individual members comprising them,and in the elements comprising the horizontal and vertical members.In these more complex frames, elements may be repeated, but the structure relies for its effectiveness on mutual support in three dimensions (see Figure 1(b)).

 

Multi-storey building frames comprise beams and columns,generally in an orthogonal arrangement. The grillage of members in the floor structure generally comprise secondary beams that support the floor slab and primary beams that support the secondary beams.The primary beams tend to be heavier and often deeper than the secondary beams. Various structural alternatives for these members are presented in Chapter 4.

 

Examples of various forms of two-and three-dimensional frames

1. Examples of various forms of two-and three-dimensional frames to for men closures:

(a) two-dimensional frames(repeated to form a three-dimensional structure); and

(b) three-dimensional frames (repeated parts relying on mutual support)

2. Exposing the Frame

 

The exposure of the frame, either in part or in whole, obviously depends upon the relationship between the skeleton and external skin. The frame can be located completely external to the cladding,in which case it is given expression in the external appearance of the building. Alternatively, the frame can be located wholly internal to the cladding, in which case it may find little or no expression externally. Between these two extremes, the interaction of the frame and cladding establishes a further range of relationships. Buildings of an entirely different character emerge depending on these spatial relationships.

 

A simple example of a portal-frame structure that is continued outside the building envelope to visual effect is shown in Figure 2 In this case, the perforated cellular beams enhance the lightness of the structure whilst preserving its primary function as a rigid frame.

 

Basic building physics requirements, in terms of thermal insulation and control of condensation, also have to be addressed, particularly when the frame penetrates the building fabric.

 

Portal-frame structure created usingcellular beams

2. Portal-frame structure created using cellular beams

 

2.1 Repetition of Frames

 

An exposed structure establishes a dominant rhythm in the elevational composition. More often than not, it is a simple and singular rhythm derived from the equal spacing of the primary frames. Various examples of repeated frames to form larger enclosures with increasing complexity are shown in Figure 3.

 

An external framework or skeleton often demands greater attention to detail, but conversely permits greater freedom in choice of structure form, as the structure is no longer dependent on the spatial confines of the internal envelope. Therefore, tension structures find their true expression in external structures.

 

Various illustrations of identical frames repeated at intervals

3. Various illustrations of identical frames repeated at intervals

 

2.2 External frames

 

By selectively exposing or concealing structural members, emphasis can be given either to the primary frames, or to the wall and ceiling planes which define the building volume. In one of the early examples, Mies van der Rohe's Crown Hall building (see Figure 4),the large-span portal frame is clearly expressed, yet subtly woven into the fabric of the external wall. In other structures, a clearer distinctionis made between the external frame and building enclosure, such as by use of masts and cables in tension structures.

 

The Lufthansa terminal at Hamburg Airport uses a portal frame comprising plated box-sections to create a massive external skeleton (Figure 5).

 

 

3. Braced versus Rigid Frames

 

The fundamental structural requirement governing the design of connections in building frames is related to the strength and stiffness of the connections between the members, or of members to the foundations.

 

 

Crown Hall: external portal frame 4. Crown Hall: external portal frame (architect: Mies vander Rohe)

Lufthansa Terminal, Hamburg Airport

5. Lufthansa Terminal, Hamburg Airport (architect: VonGerkan Marg & Partners)

 

 

The connections may be one of three configurations defining these degrees of strength (or more correctly ‘resistance’) and stiffness :

 

image 6. Various forms of steel connections :

(a) examples of effectively ‘rigid’ connections; and

(b) examples of effectively ‘pinned’ connections

 

 

1.  Rigid (also called fixed or moment-resisting) connections(Figure 6 (a)).

2.  Pinned (also called simple) connections (Figure 6 (b)).

3.  Semi-rigid (also termed partial strength) connections.

 

 

Rigid frames require rigid connections in order to provide forstability at least in one direction. Braced frames are stabilised by vertically oriented bracing, and require only pinned connections.Rigid frames are often termed ‘sway frames’, because they are more flexible under horizontal loads than braced frames.

 

In a ‘rigid’ connection there is complete structural continuity between any two adjacent members. Moment (or rigid) connections are used in frames where there is a desire to omit vertical bracing in one or both directions. The main advantage of rigid frames is that an open space between columns can be created, which offers flexibility in choice of cladding, etc. (e.g. in glazed façades). However, the achievement of full continuity between members at the connection requires an extensive amount of fabrication and, as a consequence, this system is relatively expensive.

 

To achieve a nominally ‘pinned’ joint, the connections are made so as to permit the transfer of axial and shear forces, but not bending moments. Nominally simple connections may provide some small degree of rigidity, but this is ignored in structural design and these connections are treated as pinned. Examples of pinned connections are cleated, thin or partial depth end-plates, and fin-plate connections as illustrated in Figure 6(b).

 

Pinned connections are usually simple to fabricate and erect, and are the least expensive type of connection to produce. As a consequence, lateral stiffness must be introduced into the frame by other means.

 

Semi-rigid (and also partial strength) connections achieve some continuity through the connections, but are not classified as full strength, as they do not achieve the bending resistance of the connected members. These forms of connections are illustrated later on in Figure 5. They are used for low-rise frames in which horizontal forces are not so high, or in beams where some end fixity is beneficial to the control of deflections.

 

 

4. Portal-Frame Structures

 

Portal-frame type structures are examples of rigid frames that can take a number of forms. They were first developed in the 1960s, and have now become the most common form of enclosure for spans of 20 to 60 m. Portal frames are generally fabricated from hot-rolled sections, although they may be formed from lattice or fabricated girders. They are braced conventionally in the orthogonal direction.

 

In general, portal-frame structures are used in single-storey industrial type buildings where the main requirement is to achieve a large open area at ground level and, as such, these structures may not be of architectural significance. However, the basic principles can be used in a number of more interesting architectural applications, as illustrated in Figures 2 and 7. Also, portal frames can be used in other applications, such as in roof structures for multi-storey buildings, long-span exhibition halls, and atrium structures.

 

The frame members normally comprise rafters and columns with rigid connections between them. Tapered haunches are introduced to strengthen the rafters at the eaves and to form moment-resisting connections. Either pinned or fixed bases may be used. Roof and wall bracing is essential for the overall stability of the structure, especially during erection. Typical examples of portal-frame structures using hot-rolled sections, fabricated sections and lattice trusses are illustrated in Figure 8. Portal frames generally provide little opportunity for expression but, with care, the chosen details can enlighten the appearance of these relatively commonplace structures.

 

Portal frame expressed internally behind a glazed-end elevation 7. Portal frame expressed internally behind a glazed-end elevation

of a building for Modern Art Glass (architect:Foster and Partners)

 

 

Other applications of portalised structures are illustrated in Figures 9 and 10. The articulated lattice structure using tubular elements was used to great effect in the Sainsbury Centre, Norwich.An arch or mansard shape can be created from linear members, as in Figure 11.

 

In tied portals, the horizontal forces on the columns may be restrained by a tie at, or close to, the top of the column. Ties are usually not preferred because they can interfere with the headroom of the space. Long ties also require intermediate suspension support to prevent sag. However, ties can be detailed effectively, as illustrated in Clatter bridge Hospital in Figure 12.

 

 

Typical portal structures using a variety of members 8. Typical portal structures using a variety of members

 

 

Articulated lattice portal structure 9. Articulated lattice portal structure (often using tubular sections)

 

 

Arched portal using tubular sections

10. Arched portal using tubular sections

 

 

Long-span portal frame used to create an arch structure

11. Long-span portal frame used to create an arch structure

 

Tied portal frame used at Clatter bridge Hospital

12. Tied portal frame used at Clatter bridge Hospital (architect: Austin-Smith: Lord)

 

5. Expressing the Connections

 

Connections exert a strong influence on the architectural form.Pinned and rigid connections are quite distinct and produce quite different forms and details. The discontinuity of a pinned connection can either be accentuated and given a clear expression in the structural form, or, alternatively, it can be made less apparent. By drawing such distinctions in relation to the individual frame, and then to the whole building form, offers the basis for expression.Rigid connections demand continuity between members and invite a different approach. They are required to transfer high moments and can appear heavy and complex. However, a rigid connection may also be achieved through parts that are pin-jointed,as simplified in Figure 13, and by example in the Sainsbury Centre in Figure 1. In these cases, moments are transferred by tension and compression in the connections.

 

 

Centre Pompidou, Paris 14. Example of continuity achieved through a series of pinned connections,

Centre Pompidou, Paris (architect : Renzo Piano and Richard Rogers)

 

The end wall of the Centre Pompidou in Paris, shown in Figure3.14, illustrates an unusual application of the principle, where the typical pinned connection between the truss and column is elegantly transformed to a moment-resisting connection by the addition of a continuous tie from the ‘gerberette’ extension to the truss and attached to the foundations.

 

Depending upon the exact nature and locations of connections in a frame, the ‘reading’ of the individual members and the frame as a whole can vary markedly. This is further illustrated in Figure 15 for a three-bay frame, in which different formal relationships between members and individual bays are established by simply varying the locations of the pinned connections in the structure. All cases are structurally admissible, but can create entirely different details.

 

Different overall forms of the frame

15. Different overall forms of the frame by varying type

and location of pinned connections

 

 

A good example of articulation within a structure is illustrated in Figure 16. Inclined ‘arms’ support slightly curved rafters and create a portal frame effect, allowing the connections to be expressed as nodes.

 

Portal-frame effect

16. Portal-frame effect created using inclined pinned members

6. Alternative Forms of Bracing

Nominally pin-jointed frames are braced in the vertical and horizontal directions. ‘Braced’ structures can be achieved in a variety of ways, including full-height bracing of a bay between columns, or a shorted ‘knee’ bracing to achieve hybrid action between a braced and a sway frame (as illustrated in Figure 17).

 

 

Examples of rigid and braced frames 17. Examples of rigid and braced frames

 

 

 

Often, the floor structure can act as ‘plan’ or horizontal bracing,but in single-storey buildings, separate horizontal bracing is required in the plane of the roof to transfer loads to the vertical bracing in the walls or cores.

 

 

6.1 Vertical Bracing

 

The stability of the building is dependent on the form and location of the vertical bracing, or other shear-resisting elements which are linked by floors or horizontal bracing.For simplicity, vertical bracing is located in the façade or internal separating walls. Ideally, the bracing line would be on the centre-line of the main columns, but this may conflict with the location of the inner skin of external walls. Discussion between the architect and the structural engineer at an early stage can resolve this difficulty. Often,flat steel bracing elements are located in the cavity of the masonry wall to minimise these dimensional problems.The most common arrangements of bracing in multi-storey construction is ‘X’, ‘V’ or ‘K’ bracing using steel angle or circular hollow sections (see Figure 18). Inverted ‘V’ bracing is preferred where substantial openings, e.g. doors, are required in the braced bay. To reduce its visual impact, bracing is often positioned around vertical cores, which usually house the lifts, stairs, vertical service ducts and/or toilets, or on the external face of the building within the cavity wall.

 

Figure 18 also illustrates the forces in the individual members.In the X-braced form, the members may be designed to resist both tension and compression, or tension only, which leads to more slender members. Tension rods or flat plates are largely ineffective in compression, and, therefore, forces are resisted only in tension when using these elements. In the K- and V-braced forms, the members must be designed to resist tension and compression, depending on the direction of the forces on the building. Tension ties are not possible in this case.

 

 

Different forms of bracing and their forces

 18. Different forms of bracing and their forces

 

 

Tension tie members are generally used in exposed steel work because of their apparent ‘lightness’. In X-braced frames, special brackets may be included to allow connection of the four tie members at the cross-over points. An example of an X-braced structure using CHS sections with a connecting plate is illustrated in Figure 19.

 

 

X-bracing using CHS sections used at a sports centre in Hampshire 19. X-bracing using CHS sections used at a sports centre in Hampshire

(architect : Hampshire County Council)

 

A ‘hybrid’ between a rigid frame and a braced frame can be achieved by the use of ‘knee’ bracing. In this case, the corner junction between a beam and column is stiffened by a short bracing member, which is designed to resist either tension or compression (see Figure 17). The bracing member transmits a force to the beam or columns, which is resisted by bending in these members. If necessary,knee bracing can be expressed as an architectural feature by curving the members or by using cast inset pieces.

 

 

6.2 Concrete or Steel Cores

 

As an alternative to bracing the external walls, the lift shafts and stairwells can be used as rigid ‘cores’ to stabilise the structure. Braced or steel-plated cores can be erected along with the rest of the steelwork, whereas concrete cores are generally built in advance of the frame and can be slower to construct. Accuracy is required for the installation of lift guide rails,3which is affected by the verticality and accuracy of the cores. Furthermore, multiple openings for service penetrations and doors can affect the stabilising effect of the core. It is not unusual for a large building to have more than one type of bracing system or core, depending upon the structural requirements and relative positions of the cores on plan.

Structural Materials - Masonry

Posted by HB on Monday, November 8, 2010 , under | comments (0)



Chartres Cathedral

1. Introduction

 

The shapes which are adopted for structural elements are affected, to a large extent, by the nature of the materials from which they are made. The physical properties of materials determine the types of internal force which they can carry and, therefore, the types of element for which they are suitable.Unreinforced masonry, for example, may only be used in situations where compressive stress is present. Reinforced concrete performs well when loaded in compression or bending, but not particularly well in axial tension.

 

The processes by which materials are manufactured and then fashioned into structural elements also play a role in determining the shapes of elements for which they are suitable. These aspects of the influence of material properties on structural geometry are now discussed in relation to the four principal structural materials of masonry,timber, steel and reinforced concrete.

 

2. Masonry

 

Masonry is a composite material in which individual stones, bricks or blocks are bedded in mortar to form columns, walls, arches or vaults (Fig. 3.1). The range of different types of masonry is large due to the variety of types of constituent. Bricks may be of fired clay, baked earth, concrete, or a range of similar materials,and blocks, which are simply very large bricks,can be similarly composed. Stone too is not one but a very wide range of materials, from the relatively soft sedimentary rocks such as limestone to the very hard granites and other igneous rocks. These ‘solid’ units can be used in conjunction with a variety of different mortars to produce a range of masonry types.All have certain properties in common and therefore produce similar types of structural element. Other materials such as dried mud, pisé or even unreinforced concrete have similar properties and can be used to make similar types of element.

 

The physical properties which these materials have in common are moderate compressive strength, minimal tensile strength and relatively high density. The very low tensile strength restricts the use of masonry to elements in which the principal internal force is compressive, i.e. columns, walls and compressive form-active types such as arches, vaults and domes.

 

In post-and-beam forms of structure it is normal for only the vertical elements to be of masonry. Notable exceptions are the Greek temples (see Fig. 7.1), but in these the spans of such horizontal elements as are made in stone are kept short by subdivision of the interior space by rows of columns or walls. Even so, most of the elements which span horizontally are in fact of timber and only the most obvious, those in the exterior walls, are of stone. Where large horizontal spans are constructed in masonry compressive form-active shapes must be adopted (Fig. 3.1).

 

Chartres Cathedral

Fig. 3.1 Chartres Cathedral,France, twelfth and thirteenth centuries.

The Gothic church incorporates most of the various forms for which masonry is suitable. Columns, walls and compressive form-active arches and vaults are all visible here.

 

Where significant bending moment occurs in masonry elements, for example as a consequence of side thrusts on walls from rafters or vaulted roof structures or from out-of-plane wind pressure on external walls, the level of tensile bending stress is kept low by making the second moment of area of the cross-section large. This can give rise to very thick walls and columns and, therefore, to excessively large volumes of masonry unless some form of ‘improved’ cross-section (see Section 4.3) is used. Traditional versions of this are buttressed walls. Those of medieval Gothic cathedrals or the voided and sculptured walls which support the large vaulted enclosures of Roman antiquity (see Figs 7.30 to 7.32) are among the most spectacular examples. In all of these the volume of masonry is small in relation to the total effective thickness of the wall concerned. The fin and diaphragm walls of recent tall single-storey masonry buildings (Fig.3.2) are twentieth-century equivalents. In the modern buildings the bending moments which occur in the walls are caused principally by wind loading and not by the lateral thrusts from roof structures. Even where ‘improved’ cross-sections are adopted the volume of material in a masonry structure is usually large and produces walls and vaults which act as effective thermal, acoustic and weather tight barriers.

 

 

external walls Fig. 3.2 Where masonry will be subjected to significant bending moment, as in the case of external walls exposed to wind loading, the overall thickness must be large enough to ensure that the tensile bending stress is not greater than the compressive stress caused by the gravitational load. The wall need not be solid, however,and a selection of techniques for achieving thickness efficiently is shown here.

 

 

The fact that masonry structures are composed of very small basic units makes their construction relatively straightforward. Subject to the structural constraints outlined above, complex geometries can be produced relatively easily, without the need for sophisticated plant or techniques and very large structures can be built by these simple means (Fig. 3.3). The only significant constructional drawback of masonry is that horizontal-span structures such as arches and vaults require temporary support until complete.Other attributes of masonry-type materials are that they are durable, and can be left exposed in both the interiors and exteriors of buildings. They are also, in most locations, available locally in some form and do not therefore require to be transported over long distances. In other words,masonry is an environmentally friendly material the use of which must be expected to increase in the future.

 

Town WallsFig. 3.3 Town Walls, Igerman, Iran. This late mediaeval brickwork structure demonstrates one of the advantages of masonry, which is that very large constructions with complex geometries can be achieved by relatively simple building processes

Portable Generators – Honda EB Series

Posted by HB on Sunday, November 7, 2010 , under | comments (0)



Portable Generators

 

Honda Power Equipment, a division of American Honda Motor Co., Inc., markets a complete range of outdoor power equipment, including outboard marine engines, general purpose engines, generators, lawnmowers, pumps, snow blowers, tillers and trimmers for commercial, rental and residential applications. Honda’s solid reputation and dependable products are what have made Honda generators a brand leader among builders everywhere. In fact, a recent Independent Survey of Construction and Industrial Users rated Honda #1.

 

Power You Can Trust Honda’s legendary industrial generators have earned a reputation in the construction and rental industries for their proven, rugged reliability. Within Honda’s industrial generators category are four Honda EB series models, each producing quiet and fuel efficient power. The EB series of generators are offered in 3,000, 3,800, 5,000, and 6,500 watt sizes. These durable generators are available through Honda Power Equipment dealers nationwide.

 

All EB models share a number of features that make them ideally suited for commercial and construction applications.

 

• Full Frame Design: Offers added protection and durability

• Automatic Voltage Regulator (AVR): Delivers regulated, consistent power, and provides reliable flow of energy and protection for powering the most sensitive of equipment.

• Wheel Kit & Hanger Kit: Allow for easy transport and lifting and securing of the units.

• Quiet Operation : Results from the use of inherently quiet four-stroke engines, acoustically tuned muffler and airflow systems.

• 3 Year Warranty: 3 year residential and commercial warranty.

 

 

Honda EB 6500 X

 

The EB3800, EB5000, and EB6500 generators are ground fault circuit interrupter (GFCI) protected to meet OSHA jobsite regulations and offer longer run times, additional outlets for convenient use, and stronger, more durable frames.

 

All Honda EB series generators are powered by Honda GX Series commercial grade, overhead valve (OHV) engines. These engines are known for their exceptional ease of starting and fuel efficiency. Honda’s comprehensive product line consists exclusively of 4-stroke engines.

 

 

for more information please visit www.hondapowerequipment.com

Honda Generators

Automatic Standby Generators—The Severe Weather Solution

Posted by HB on , under | comments (0)



Automatic Standby Generators

 

No matter where you live, severe weather—be it from hurricanes or ice storms—can arrive without warning and cause homeowners to lose power for days or even weeks. Not only is this costly and inconvenient, it’s also dangerous. Homeowners are increasingly aware of the value of having a standby generator.

 

“Residential, standby generators offer builders a tremendous value-added opportunity,” says Clement Feng, executive vice president, marketing. Generac Power Systems, the premier manufacturer of both standby and portable power generators. “It’s easy to offer standby generators as an upgrade or as part of a package, which adds to both the cachet of the home and the builder’s bottom line.”

 

Standby Power Is An Upgrade That Offers Security To Home owners Generac introduced the first automatic home standby system in 1989 and today is the industry leader, offering the broadest product line. “Automatic standby generators aren’t just high-end products,” Feng explains. “The latest models run quieter, cost less and are easier to install, making them a highly desirable enhancement to the comfort and value of any new home.” And best of all, automatic standby generators operate on natural gas or liquid propane vapor, so there are none of the fuel storage, spillage, spoilage or odor concerns that are common with gasoline or diesel models.

 

Generac

 

As the leading manufacturer of stationary generators, Generac’s new products incorporate the innovative technologies and features builders have come to expect, including :

 

The NEW CorePower™ System is compact in design with an all-weather enclosure. A high-quality product that is cost-efficient.

 

The Generac® Guardian Series meets the power needs of any home. Now the state-of-the-art Nexus™ Control System is standard and allows the generator to digitally manage up to six high-power loads. This upgrade reduces the size of the generator required for mid- to larger-sized homes making them more affordable than ever for homeowners.

 

 

Quiet Source series, the premium line of automatic standby power. A specially designed engine runs quieter at lower engine speeds, extending the life of the unit.

 

 

for more information please visit www.Generac.com

Generac

Good House Keeping

SecureKey Locksets/Hardware

Posted by HB on , under | comments (0)



SecureKey

 

SecureKey™—The Only Lock You Can Re-key With A Key

When it comes to revolutionary products, SecureKey from Schlage is leading the way for locks. This new re-keyable cylinder has 10 times more key combinations than the nearest competitor. Meaning only Schlage can make a home 10 times more secure from key duplication. Plus, it’s bump and pick resistant, so it’s sure to leave a legacy of security that lasts for generations. It’s also a faster, more cost-effective way to reinforce jobsite security. It all adds up to a turnkey solution that will change the way you think about re-keyable locks.

 

Quick And Easy. Safe And Secure.SecureKey locks and deadbolts employ a new high-security design that enables them to be rekeyed in seconds—without removal from the door and without compromising security. In fact, security is actually enhanced through the use of a pick-resistant Grade 1 cylinder and a special locking sidebar that protects against bumping. And the lock is secure even when it’s in the rekey position, which is not the case with other re-keyable locks on the market.

 

SecureKey

 

 

schlage

For more information visit www.securekey.schlage.com