Willis’s Elements of Quantity Surveying free download

Willis’s Elements of Quantity Surveying free download

Whilst it is recognized that modern computerized measurement techniques utilizing standard descriptions might appear far removed from traditional taking off , it is only by fully grasping such basic principles of measurement that they can be adapted and applied to alternative system.  

Contents  of Elements of Quantity Surveying

Setting down dimensions

Alternative system

Applied mensuration

General rules for taking-off

Substructures

Walls

Floors

Roofs

Internal finishes

Windows and doors

 Reinforced concrete structure

Structural steel work

Plumbing

Drainage

External works

Demolitions, alternations and renovations

Preliminaries

Bill preparation

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Tension membrane structures

Tension membrane structures offer an aesthetic,  practical, and cost-effective way to provide roofing to either new or existing areas. These shade  supporting structures have been put into use for most  part of the twentieth century and have found wide  spread applications including, sports facilities,  convention centres, concert halls, shade roofs of large  commercial buildings, airport roofs, gas stations and terminals, to mention only a few.  The membrane part in the structure is pre-stressed and thus enables the structure to maintain its form.

 Two types of shapes are found in tension membrane  structures. The first type is the 'anticlastic structures' with two double curvatures in the  opposite direction while the second is a   'synclastic structures' with the double curvatures  in the same direction. Anticlastic structures can  take a variety of shapes and forms including,  the arched vault, hyper and cone. Technically speaking a tension membrane  structure is a combination of elements, which carry only tension and no compression or bending. This  is the reason why the use of compression rings or  beams, that form the bending or compression elements,  is used in most tensile structures.

Why Tension Membrane Structures?

The semi-translucent nature of fabric structures is  what makes them a favourite with engineers and architects looking for roofing systems to cover large  areas, such as sports stadia or terminals. Fabric  structures help in increasing the sustainability quotient of  a building in more ways than one. The fabric allows for  entry of natural light, while cutting down the  transmission of heat. The high reflectivity of the  membrane makes it an ideal alternative to glass as a  roof glazing system.  Tension membrane structures are usually reinforced  using either PVC /Polyester or PTFE based coatings. This makes the fabric structure perform well from the fire  performance perspective too. For example, a tension membrane structure with PTFE coating is rated non  combustible as per ASTM 136, making them completely safe. Additionally the inert nature of the fabric aids in  self-cleaning, a characteristic which makes them  perfectly suited for application over large areas.

The  dependency on artificial lighting is vastly reduced. The unique properties of light reflectance and  transmission also offer exciting possibilities for lighting  after dark. Directing lights under the canopy to reflect  off the underside is a great way to use uplighters, but  more even lighting can be achieved under the fabric by  shining lights down on the fabric from above.

The thermal insulation achieved with a single layer  of either PVC/Polyester or PTFE membrane with a typical weight of around 1200gm per sq metre and a  U value of approximately 4.5 W/m2K, is more or less  similar to that of glass. White is mostly the preferred  colour when it comes to tension membrane structures.  This is because with dark coloured membranes, the  absorption of heat is very high. Dark coloured  membranes can also re-radiate heat. White is  therefore the preferred choice in the case of tension  membrane fabrics.

Roofing and Cladding

With tension membrane structures, it is possible to  have both the roofing and cladding in one single structural element. Typically the seam and curve of the  fabric structure that reflects the tension is aesthetically  pleasing, while also being important for the structural  integrity. Due to the integration of the roofing and  cladding, the structures are also easy to clean and  maintain, when compared to glaze glass roofing. The  roof, in the case of tensile membrane structures is  factory welded and therefore easy to install, apart from  acting as a weatherproof skin that does not contain  expansion joints. All these factors enable rapid  construction and coverage of large areas.

Span Capabilities

An excellent span capability is another factor that  puts fabric ahead of other materials. While every other  possible roofing material requires rigid intermediate  support, it is not the case with fabric structures. The  fabric can span from one boundary to another in one  unbroken (sweep). This ensures that there are no sealing  related issues that need to be addressed. The amazing tensile capacity of fabric helps to  reduce the number of components that make up the  supporting framework to a minimum, thus enabling a  structure that is much more light-weighted when  compared to other types of construction. On the flip side  though, the structures incorporating the concept need  large foundations in order to prevent wind currents  lifting the canopy. This factor is offset by the fact that in  terms of cost foundations are cheaper to prepare, than  the visible above ground construction components that  are exposed to the vagaries of weather and therefore,  more prone to damage. 

Project information for cost analysis

Project information for cost analysis

1.        1.  Building type

CI/Sfb classification  will be given and restriced to the Built environment classification taken from table 0

2.       2. BCIS code

The BCIS reference code classification buildings by the form of information, number of storey’s and gross internal floor area in square meters.

The different construction classes are.

·         Steel framed construction

·         Reinforced concrete framed construction

·         Brick construction

·         Light framed steel construction

A single-story building of 766 square metres of gross internal floor area and built in traditional construction would have the following BCIS code.

c-1-766

3.       3. Client

Indication should be given of type of client, eg borough council, church authority, owner occupier, government department, property company, etc.

4.       4. Location

The location of the project should be given, noting the city or the country borough or alternatively the borough and the country, eg Bristol, or Richmond, Surrey. The location may be reported less precisely if the client so desires.

5.       5. Tender date

Date fixed for receipt of tenders.

The date of tender ie 10 days before  date of receipt.

6.      6.  Brief description of total project.

Brief description of the building being analyesed and of the total project of which it forms part.

Any special or unusual feasures affecting the overall  cost not atherwise shown or detailed in the analysis.

7.      7.  Site conditions

·         Site conditions with regard to access, proximity of other buildings and construction difficulties related to topographical or climate conditions.

·         Site conditions prior to building, eg woodland, exting building, ect.

8.     8.   Market conditions

   Short report on tenders indicating the level of tendering, local conditions with regard to availability of labour and materials, keenness and competition.

9.       9. Contract particulars of totalo project

a.       Type of contract, eg JCT (with or without quantities ), GC/Wks/I,ect.

b.      Bills of quatities, bills of approximate quantities, schedule of rates.

c.       Open or selected competition, negotiated, serial or contituation or both.

d.      Number o contractors to which tender documents sent.

e.      Number of tenders received.

f.        Firm price or if fluctuating whether for labour or materials or both.

g.       Contract periods:   (i) stipulated by client;

                                                   (ii) quoted by builder.

10.  10.  Tender list

a.        List of tenders received in descending value order.

b.      Indicate whether tenders were from local builders (L) or builders acting on a national scale (N)         

CONSTRUCTION WATERPROOFING

 The building envelope is equivalent to the skin of a building. In essence,a structure must be enveloped from top to bottom to prevent intrusion from nature’s elements into interior spaces and to protect the structural components from weathering and deterioration. Envelopes complete numerous functions in a building’s life cycle,including

● Preventing water infiltration

● Controlling water vapor transmission

● Controlling heat and air flow,into and out of interior spaces

● Providing a shield against ultraviolet rays and excessive sunlight

● Limiting noise infiltration

● Providing structural integrity for the façade components

● Providing necessary aesthetics

● Preventing of mold formation and growth

CONTENTS

Chapter

1. Waterproofing Principles—The Building Envelope

2. Below-Grade Waterproofing

3. Above-Grade Waterproofing

4. Residential Waterproofing

 5. Sealants

6. Expansion Joints

7. Admixtures

8. Remedial Waterproofing

9. Mold

10. The Building Envelope: Putting It All Together

11. Life Cycles: Quality, Maintenance, and Warranties

12. Envelope Testing

13. Leak Investigation and Detection

14. Safety

15. Guide Specifications for Waterproofing

16. Resources

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Iseami House, Costa Rica

The Iseami House by Robles Arquitectos is a work of science as much as it is an achievement of design.  This home rests on a hill above the ocean on the Peninsula de Osa in Costa Rica, a location with 5% of the world’s biodiversity– yet 20km away from the nearest town.  To build such a home, Robles Arquitectos were tasked with designing a fully grid-free, self-sustainable structure that could manage the demands of this hot, humid environment.

RoblesArq has followed their design process named: SDRA (Dynamic system Robles Arquitectos) which, during the investigation stage,evaluates 10 important elements as: Site, Climate, Energy, Water, Materials, environment, atmosphere, cost, innovation with the use of passive strategies and the implemented processes.These elements will be analyzed to develop a design plan and a management plan during the building lifecycle in order to reduce the negative impact this house could bring to the natural environment and then, to minimize the negative impact that nature could create in the building, this because our main concept is to create a very low maintenance house.

The secluded project site is located at 30 km from the closest town, Puerto Jimenez, therefore, the house doesn’t have any public service supply as electricity or water, and this condition obligates the institute to invest on a 100% self-sufficient house. During the design process, decisions were takenin order to bring the water and energy supply.

 The existence of a water concession on the protected forest inside the property, allows the project to consider a natural potable water source for its use, then the water volume is utilized in order to produce energy with 2 low impact hydroelectric generators that generate a total of800KW/H.Furthermore, Casa Iseami becomes a solar power plant with a production capability of 10.800KW/H, this because the roof has been designed in order to have the orientation and position to maximize its production. The roof material has great structural capacities, so the access to the roof for maintenance is possible (The use of a solar hot water tank provides comfort to the users). The hybrid energy systemprovides with success enough energy to the project, the caretaker’sand maintenace housing and the existing lodge for the participants of the institute.

 

The materials for the house were selected following the results given by an investigation process done to the existing project near the site. This way we took the results and then decide which were the best materials to use in order to create a low maintenance project. All the proposed materials were tested in order to evaluate its behavior on the difficult environment that the Osa peninsula has because of its humidity, high percentage of rain, mould, fungi and its flora and fauna.

The structural and electro mechanic design has been inspired on an exo-skeleton insect, this way the creation of open spaces between walls and ceilings are eliminated, creating a benefit for the indoor air quality because we avoid the creation of mould and plagues common in the projects around.
 

Within the chosen materials, the thermal-panels (Versawall and Versapanel by Centria) are chosen as the main material for walls and roof because of its solar reflectance index, structural and acoustic properties and ability to give the thermal comfort without using empty spaces on the walls. This material brings the opportunity to build the house, piece by piece as a Lego, a great strategy to minimize the use of transportation in order to lower the carbon footprint of the institute and the ability to build the house with fast and minimum labor on this secluded location. Because of the high structural capabilities of the material, the amount of steel structure was lowered considerably, saving the use of the natural resources needed for the anti-seismic structure. Furthermore the thermal-panel is a very light and easy to install, low maintenance and highly resistant material for humidity.

Passive design strategies have been successfully implemented to handle the sun exposure, relative humidity, natural illumination and ventilation inside the bioclimatic considerations of the project. Relative humidity is managed to create a healthy and comfortable space. The strategies used are, elevating the house 1 meter above the ground (water permeability in the ground will be possible), ideal orientation (Southeast-northwest)for cross ventilation and the installation of two polycarbonate skylights that provide the control of sunlight exposure in the interiors of the house, preventing UV to damage the furniture and Indoor environmental quality for its occupants. Large overhangs create shadows all day long in order to control the interior temperatures and natural illumination together with the thermal capacities and white color of the envelope. The use of recycled plastic louvers (Trex) creates a second envelope that surrounds the house in order to maximize the temperature control and rain exposure.On the other hand, the white color in the totality of Iseami has the goal to be able to visualize any insect or mould creation inside the house, frame and create a contrast with nature, maximize natural light and solar reflectance index (SRI 100). The roof design allows the occupants to have an integration with the mountains around with an “open to the sky” concept, this way, cross ventilation, daylight and views are present in every single space around the house.

One important goal of Iseami house was its recyclable potential, therefore, the material selection needed to be 100% recyclable at the end of its lifecycle, therefore, recycled plastic, glass and mainly the steel (structure and panels) have been choose for the project. Plastic materials at the interior are not included to avoid the outgassing of any toxic compound found in certain plastics, sealants or aditives. Instead, the Versawall and regional materials as white mosaic floors creates a simple but well balanced interior.
The construction system is based on a prefab method planned in order to get the construction time and low environmental impact on the site. The main benefit about that is the adaptation and evolution potential with the community inhabitants, which have a poor economy and will be able to imitate these solutions in different scales with very simple materials.

The distribution of the house looks for a new way of living where all the activities have the possibility to be developed outside, this way the integration between the interior and the exterior become succesfull and natural, creating possibilities to enjoy nature on its original state as much as the occupants desires it.
Iseami House is the result of an investigation during the design process of a tropical house built on a remote and difficult site in which the main objective was to promote the benefit of the well being of the community and its occupants, all thru an emergent tropical architecture concept.

Ground floor plan

second floor plan