Disclaimer: This work has been submitted by a student. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of Project Rise
Analysis of restrictions to access site
The project is the construction of a 6 storey residential building in the heart of the Capital city of Sri Lanka. The construction site is just next to a main road and with two streets on either side. A boundary wall has been constructed surrounding the construction site with two access gates, one entrance and one exit since the roads are one way.
|Figure 1 – Layout plan of site|
Since the site is located in a dense environment there will be many restrictions for vehicles to access the site for delivery of materials and construction equipment. The main problems and their possible solutions are given below;
Table 1 – Site restriction issues and solutions
|Trenches and pits||Trenches and pits dug in the site for construction can hinder the movement of vehicles to the working site||This can be solved by constructing temporary bridge or support structures so that vehicles can move within the site also proper signs can help avoid accidents|
|Traffic congestions||As the construction site is situated in the city centre there will be a lot of traffic which can cause hindrance to the transportation of material and equipment to the site||By transporting materials in non- rush hours and during night time or by travelling using an alternative non traffic path it is possible to avoid traffic hindrance.|
|Alternate route blocked||Alternative roads or potential alternative routes to the site might be blocked by small water ways or trenches||It is possible to build a small temporary bridge so that there can be access to the site from the alternative route|
|Pedestrians and Public parking at entrance||Pedestrians walking across the site entrance and people parking vehicles at the entrance can obstruct access to the site||Can be solved by appointing a traffic coordinator at entrance and by placing proper sign boards|
|Temporary structures and plants||Temporary structures such as falsework and form work and plants made for construction can obstruct movement of vehicles within site||This can be solved by preplanning locations of temporary structures and plants so that a path for vehicular movement can be retained|
|Unloading near access gates||If the store is located near the access gates, the vehicles parked to unload can restrict access to other vehicles to the site||This can be solved by locating the stores away from the access gates|
|Adverse weather conditions||Improper drainage within the site can cause blockage to the access gates||Can be solved by constructing temporary drainage system within the site to control storm water collection|
Equipment and plant requirement analysis
The construction of a multi-storey building requires many equipment and plants. The process of identifying the equipment and plants required is a crucial part of the project. The process of identification of the equipment and plant required for the construction can be divided into 3 steps;
- List each construction process in the construction of the building in chronological order and then list each activity to be performed for each construction process.
- Compute the magnitude of each activity – that is how large the activity is and how much labour and time required to complete the activity. The magnitude of each activity can be extracted directly from the BOQ or can be calculated using dimensions in the blueprint of the structure E.g. – the no. of m3 of earth to be removed during excavation, the no. of kilos of concrete to be mixed by the concrete mixer and etc.
- Using the magnitude and amount of labour required for each activity we can list the equipment and plant required based on the catalogue of the equipment or based on past experience of the contractor. E.g. shallow excavations can be done using shovels but deep excavations require large excavators hence by finding the magnitude of the excavation to be done we can decide on which equipment is required for the process and with the amount of labour we can decide the no. of equipment required.
Consider the construction of a 5 storey building, the equipment and plants required till the construction of the first floor are listed below;
Table 2 – Equipment/ Plant required for construction
|Construction process||Construction Activity||Equipment and plant required|
|Setting Out||Site Clearing||Dump truck, bull dozers, chain saw and shovels|
|Setting out||Total station, tread, nails and pegs|
|Excavation for Base||Removal of earth||Excavators, bulldozers, trenchers and skid loaders|
|Disposal of earth||Lorry, dump truck and skid loader|
|Pumping out seeping water||Hydraulic pump and water tank|
|Construction of base||Piling||Pile driving rigs and pile driving hammers|
|Construction of basement walls||Concrete mixer, formwork and falsework|
|Preparation of Reinforcement cages||Bending steel||Steel bending machine|
|Welding steel||Welding plant and Welding torch|
|Construction of Columns and Beams||Concreting||Concrete mixer, formwork and falsework|
|Compacting||Mechanical vibrators and three wheel roller|
|Curing||Water absorbent sheets and water sprayers|
|Construction of slabs||Concreting||Concrete mixer, formwork and falsework|
|Compacting||Mechanical vibrators and three wheel roller|
|Curing||Water absorbent sheets, water sprayers and water tanks|
Sub- Contractor management
Piling is one of the first and crucial phases of the construction of a building therefore it is important to make sure that the process is completed on time to avoid delays in the overall construction. By using processes described in NEC3 Conditions of Subcontract and by using other project management techniques it is possible to make sure that the piling activity is completed on schedule without compensating on the quality of the work. The following steps are recommended;
Conduct regular meeting to discuss progress and solve issues – According to NEC3 Conditions of Subcontract clause 30.2 it is compulsory for the subcontractor to forecast the date of completion to the contractor every week and according to clause 16.1 it is compulsory to notify the contractor of factors that impair the performance of subcontractors work. Therefore during the course of the contract it is vital to keep regular meeting with the project manager and the engineer of the sub-contracting company so that it is possible to keep in track of the progress of the project and to solve any issues that has arouse after the commencement of the contract.
Request sub-contractor for weekly program of works – According to NEC3 Conditions of Subcontracts clause 31.1 it is compulsory for the sub-contractor to submit the programme of works to the contractor which contains a rough itinerary of the works to be completed each day during the course of the contract. This can be used as a way to track the progress of the sub-contractor’s work. Using the itinerary it is possible to predict if there will be any clashes between the piling and any other construction activity that is to be done in the site at the same time and it will be possible to device plans to avoid the clash so that the piling activity can go according to the itinerary. For example the construction of temporary plants and delivery of construction materials can take place during the piling phase therefore there is a large probability that the other activities can hinder the piling activity therefore with prior preparation it is possible to avoid clashes between the activities and to avoid delays in pilling. Further the itinerary will help to find out if the piling activity is not going on schedule hence during the regular meeting it is possible to discuss ways to speed up the pilling activity to catch up with the schedule.
Release funds to sub-contractor depending on the work completed – According to NEC3 Conditions of Subcontract clause 50.3, 50.6 and 50.7 it is possible to release funds based on the completion of works which is assessed monthly. This will encourage the subcontractor to complete the piling on time so that the payment can be received quickly since delays in piling work will sum to delays in payment which can cause a financial burden on the company.
Claim delay damages from sub-contractor – According to NEC3 Conditions of Subcontract clause 50.5 it is possible to impose delay damages on the subcontracting company which is to be paid in term on the no of days delayed. This can be used as a mechanism to encourage the subcontracting company to complete the work on time. Likewise the contract can also introduce a reward or bonus to the subcontracting company for early completion of the piling activity which can also help encourage them to perform quickly and finish on time.
Only select sub-contracting company capable of delivery project on schedule – Choosing to give the sub contract to companies with the sufficient capital and financial capacity to complete the project on time can be a way to make sure that the piling activity is completed on time since smaller companies without proper equipment might not be able to complete the project on time.
Decide on duties and responsibilities of the sub-contractor before making contract – Deciding what are the duties and responsibilities of the sub-contractor and clearly stating them on the contract is crucial to make sure the piling activity is completed on time. Duties and responsibilities such as who provides the piling equipment and who is responsible for clearing of construction waste after completion of piling are some of the major issues which needs to be clearly communicated with the sub-contractor before signing contract since disputes arising after contracting can delay the entire construction process.
The following is the activity schedule for the construction of a 3 storey commercial building;
- Site Clearing – this process is the first stage of construction
- Setting out – this process will start along with site clearing. This process includes identification of boundary of the site and identification of location of new structures during construction hence this process will proceed every time a new structure such as a columns is needed to be located to construct
- Excavation for foundation – this process will start just after area to be excavated is located during setting out. It begins with excavation of earth and final stage includes removal of excavated soil from site.
- Construction of foundation – this process will start when excavation finishes and disposal of excavated soil begins. This process includes piling and construction of pile caps
- Construction of basement – this process will begin during the final stages of construction of pile caps. This process includes construction of basement floor, basement walls and water proofing of basement walls.
- Construction of columns and beams – this process will start during the final stages of waterproofing of basement. This process is repeated for every floor after the construction of the slabs for each floor until completion of the superstructure
- Construction of slabs – this process will start after the construction of beams and columns for each floor and will repeat for each floor until completion of super structure
- Pluming and electrical wiring – this process will start at the final stages of the construction of slabs
- Roofing and tiling – this process will start after construction of slabs and will continue simultaneously with plumbing, tiling and painting.
- Painting and installation of doors and windows – this is the final stage of the construction of the building. This is where the final interior and exterior fittings and floor rendering is done.
- Construction of Boundary wall- this process starts when the construction of superstructure finishes because this process uses the same equipment.
- Environmental protection activities – this process continues from the beginning of construction to end. The aim of this process is to minimize environmental damage. E.g. Proper disposal of construction waste.
|Table 3 – Activity Schedule|
- NEC3 (2005), Engineering and Construction Short Subcontract, Available from https://www.neccontract.com/Products/Contracts/Engineering-Construction-Contract/NEC3-Engineering-and-Construction-Short-Subcontra.html [Accessed on 19th November 2014]
- Site layout information available from http://www.cat.com/cda/layout?m=37840&x=7 [Accessed on 10th November 2014]
- Identification of equipment information available from http://www.engineeringcivil.com/theory/construction-equipments [Accessed on 20th November 2014]
- Planning layout information, Available from http://civcal.media.hku.hk/queenmary/site_planning/constraints/default.htm [Accessed on 19th November 2014]
- Dr. Ibrahim Assakkaf. 2003. piles and pile driving, equipment and methods 6th edition http://www.assakkaf.com/courses/ence420/lectures/chapter19.pdf [Accessed on 19th November 2014]
- A.j pulie pvy lt., Master finish, http://www.masterfinish.com.au/catalogue%20pdfs/mf%20product%20catalogue.pdf [Accessed on 19th November 2014]
- Goundforce shorco excavation support http://www.groundforce.uk.com/GroundforceShorco/IndustryResources/Piling+%E2%80%93+What+Exactly+Is+Piling [Accessed on 18th November 2014]
- Cosmos construction machinery’s &equipment http://www.cosmosconstructionequipment.com/handling.html [Accessed on 19th November 2014]