1.0 INTRODUCTION
1.1 Project name
CADANGAN MEMBINA BANGUNAN PEJABAT YANG MENGANDUNGI: i. 1 UNIT BANGUNAN PEJABAT 12 TINGKAT (MENARA A)
ii. 1 UNIT BANGUNAN PEJABAT 9 TINGKAT (MENARA B) iii. 1 UNIT RUANG PEJABAT BAWAH TANAH 4 TINGKAT
iv. 1 UNIT BANGUNAN GUNASAMA 2 TINGKAT YANG MENGANDUNGI KEMUDAHAN GIMNASIUM, KAFETERIA, PUSAT SUMBER, DEWAN SERBAGUNA, TASKA DAN SURAU SERTA
v. LAIN-LAIN KEMUDAHAN BERKAITAN IAITU:- a. 3 TINGKAT TEMPAT LETAK KERETA ARAS BASMEN b. 1 UNIT PENCAWANG ELEKTRIK
c. 1 UNIT RUMAH SAMPAH
DI ATAS LOT 33074 (PLOT P47), JALAN IMPACT, CYBER 6, MUKIM DENGKIL, DAERAH SEPANG, SELANGOR DARUL EHSAN
1.2 Project Description
The project covers an area of 4.86 acres (1.967 ha). The site is located within Mukim Sepang and Selangor district. Key and location plans are shown as per Figure 1 and 2 respectively.
The proposed development is generally consists of 1 main building which include 4 Basement Car Park, ancillary building and other facilities (refer Appendix A).
1.3 Project Developer/ Owner
GAGASAN PIRAMID SDN BHD
Suite 8.26, 8th Floor, Wisma Zelan,
Jalan Tasik Permaisuri 2, Bandar Tun Razak, 56000, Kuala Lumpur,
Wilayah Persekutuan.
1.4 The objective
The objective of this report is to study and plan for the earthworks and erosion sediment control based on the approval under the master layout plan. This report intends to obtain the approval of the proposed earthworks and erosion control from Majlis Perbandaran Sepang (MPS).
2.0 TOPOGRAPHY AND EXISTING DRAINAGE SYSTEM
The project site is in a terrain of undulating hills and small valleys with the range of RL 28.0m to RL 47.0m O.D.L within the development area. Currently the site is a vacant plot of undeveloped area and covered by shrubs. Infrastructure amenities such as roads, roadside drain and water pipes are already available around the proposed project area.
Key plan, location plan and aerial view of the site is shown in Figures 1 to 3 respectively.
Figure 2 – Location Plan
3.0 DESIGN THEORIES
3.1 Definition and Reference
Silt traps are the structures formed by excavation and/or construction of an embankment across a waterway or other suitable location.
The purpose is to collect and store sediments from sites cleared and/or graded during construction or for extended periods of time before re-establishment of permanent vegetation and/or construction of permanent drainage structures. It is also intended to trap sediment before it leaves the construction site.
Reference is made to the Urban Stormwater Management Manual for Malaysia (Manual Saliran Mesra Alam Malaysia – MASMA 2nd Edition) Appendix 2.B – IDF
Constants and Chapter 12 – Erosion and Sediment Control.
3.2 Design Criteria
The design criteria adopted for the sediment basins are as follows:-
• Basin type : Dry ( Table 12.16: Sediment Basin Type n Design Consideration) • Soil type : Type C–Coarse-grained sand, sandy loam: less than 33% <
0.02mm
• Design storm : Up to 10 Years ARI
• Location of fitted coefficient for IDF Curves : Setor JPS Kajang
3.3 Sediment Basin Calculations
A sediment basin calculation is based on:-
URBAN STORMWATER MANAGEMENT MANUAL FOR MALAYSIA – Department of Irrigation and Drainages, 2011 i.e. CHAPTER 12, EROSION CONTROL AND SEDIMENT CONTROL.
Detailed design of the wet sediment basin is attached in Appendix B.
4.0 PROPOSED EARTHWORKS LEVEL
Proposed platform levels are determined by considering the existing adjacent road and drainage levels. The existing topography of the sites is also considered with the intention to minimize the earthworks. In addition, the proposed platforms levels are also crucial to ensure optimize infrastructure design such as drainage and sewerage system.
Temporary access during construction to the proposed site is via existing road on the northeast part of the site, where premix road and a wash trough will be provided at the entrance. Temporary earth drains and a dry sediment basin shall also be provided and maintained during the construction period.
4.1 Cut & Fill Embankment
Cut and fill works is required to form up the platform levels. All slopes shall be designed based on the following criteria:- i) Cut: 1.0 V : 1.5 H ; Fill: 1.0 V : 2.0 H
ii) Compaction trial supplemented by any necessary field tests described in BS 1377 (Method of Testing Soils for Civil Engineering Purposes) shall be carried out before the compaction works commence. While earth fill shall not be laid on debris from clearing works to avoid unstable fill slopes.
4.2 Fill Material
Fill shall be of suitable materials in accordance to BS:1377.
4.3 Compaction of Fill
The standard of compaction to be achieved shall be related to the maximum dry density of the soil as prescribed in BS1377 Test No.12 or Mod. AASHTO Test (T-180) as follows:
a) Top 1.0 meter of all embankments, under roadways and hard standings subject to traffic, compacted material not to be less than 95% of the maximum dry density.
b) Elsewhere, dry density not to be less than 90% of the same. In-situ density tests using the sand replacement method as described in BS1377 Test No.14A or B as appropriate shall be carried out
5.0 EARTHWORKS VOLUME COMPUTATION
The computation of earthworks volume was performed using the Auto Cad 3D for Infrastructure Design. The output of the computation is as follows:-
Cut Volume : ~ 102, 642 cubic meter Fill Volume : ~ 8, 320 cubic meter ---
Nett Earth Volume : ~ 94, 322 cubic meter ====================================
6.0 EROSION SEDIMENT CONTROL PLAN (ESCP)
6.1 General Construction Conditions
• The ESCP will be read with the engineering plans or written instruction that may be issued in relation to the development at the subject site.
• Contractors has to ensure that all erosion and sediment control works are undertaken as instructed in the specification and constructed in accordance with the Urban Stormwater Management Manual for Malaysia, 1999.
• All Contractors will be informed of their responsibilities in minimizing the potential soil erosion and pollution of down slope areas.
6.2 Land Disturbance
Construction activities on proposed site have the potential to pollute storm water. These include earthworks that result in erosion and sedimentation as well as contractors’ activities.
The soil and erosion hazard of the site will be kept to a minimum as limiting land disturbance as follows:
• Construction areas – To identify the limitation of boundary of works
• Access areas – To determine the location in order to conserve existing vegetation and surroundings.
• Remaining lands – Entry prohibited except for essential management works.
6.3 Erosion and Sediment Control Measures
The following erosion and sediment control measures (BMPs) will be constructed prior to commencement of earthworks:-
• Temporary diversion of channel-earth drains. • Silt trap
• Wash trough
6.4 Erosion Control Conditions
• Hoarding will be installed as shown on the plan to ensure prohibit unnecessary site disturbance. Vehicular access to the site will be limited to only that essential for construction work and all vehicles entering the site only through established site access points.
• All earthworks including water ways, drains and their outlets will be constructed to be stable in at least the design storm event.
• Soil materials will be replaced in the same order they are removed from the ground. It is particularly important that all subsoil is buried and top soil remain on the surface at the completion of the works.
• All constructed slope will be close turfed immediately after the slope formation and construction with as low as gradient as practical.
• Where practicable, the construction programme will be scheduled so that the time starting land disturbance activities to stabilization is less than six months, if • Weather permitting.
6.5 Pollution Control Conditions
The silt trap:-
a) The silt trap has been designed in accordance with the procedures given in MSMA based on a design event of 3 months ARI. The location of sediment basins are shown in Layout Plan.
b) The silt trap will be flocculated before discharge occurs (unless the design event is exceeded).
c) Silt trap shall have one or more pegs placed on the floor to clearly indicate the level at which design capacity occurs and when sediment needs to be removed.
Sediment removed from any trapping device will be disposed off in locations where further erosion and consequent pollution to down slope lands and water ways will not occur.
Water will be prevented from directly entering the permanent drainage systems unless it is relatively sediment free.
Temporary erosion and sediment control structures will be removed only after the protected lands are stabilized.
6.6 Site Management Condition
Acceptable waste storage bins will be provided for any concrete and mortar slurries, paints, acid washings, light weight waste material and litter. Clearance services will be provided at least weekly.
6.7 Site Inspection and Maintenance
A self-auditing programmed will be established for site inspection and maintenance purposes based on the proposed interval:
(a) At least weekly
(b) Immediately before site closure
