Trenchless technology

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Trenchless technology is a type of subsurface construction work that requires few trenches or no continuous trenches. It is a rapidly growing sector of the construction and civil engineering industry. It can be defined as “a family of methods, materials, and equipment capable of being used for the installation of new or replacement or rehabilitation of existing underground infrastructure with minimal disruption to surface traffic, business, and other activities.

 

Trenchless construction includes such construction methods as tunneling, microtunneling (MTM), horizontal directional drilling (HDD) also known as directional boring, pipe ramming (PR), pipe jacking (PJ), moling, horizontal auger boring (HAB) and other methods for the installation of pipelines and cables below the ground with minimal excavation. Large diameter tunnels such as those constructed by a tunnel boring machine (TBM), and drilling and blasting techniques are larger versions of subsurface construction. The difference between trenchless and other subsurface construction techniques depends upon the size of the passage under construction.

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The method requires considering soil characteristics and the loads applied to the surface. In cases where the soil is sandy, the water table is at shallow depth, or heavy loads like that of urban traffic are expected, the depth of excavation has to be such that the pressure of the load on the surface does not affect the bore, otherwise there is danger of surface caving in.

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Trenchless rehabilitation includes such construction methods as sliplining, thermoformed pipe, pipe bursting, shotcrete, gunite, cured-in-place pipe(CIPP), grout-in-place pipe, mechanical spot repair, and other methods for the repair, rehabilitation, or replacement of existing buried pipes and structures without excavation, or at least with minimal excavation. Mechanical spot repair is applied where damaged pipelines require the re-instatement of structural integrity. Sliplining, CIPP, and thermoformed pipe lining involve pulling or inverting a new liner into an existing pipe, then applying heat and/or pressure to force the liner to expand to fill the pipe. CIPP technologies combine a carrier (felt or fibreglass) impregnated with heat, ultraviolet light, or ambient curable resin to form a “pipe within a pipe”. Pipe bursting fractures a pipe from the inside and forces the fragments outwards while a new pipe is drawn in to replace the old.[2] The other methods are primarily for fixing spot leaks. Trenchless rehabilitation methods are generally more cost-effective than traditional exhume (dig) and replace methods.

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Women are allowed to drive in the Kingdom

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Saudi Arabia is set to reap an economic windfall as millions of women are allowed to drive in the Kingdom for the first time, in a move that is expected to spur spending across a range of sectors.
Retailers, insurers and car hire companies are among the potential winners from the decision, while employers will be able to overcome one of the main barriers to boosting female participation in the workplace.

Investors inside and outside the Kingdom are today assessing the likely impact of the momentous move on the Kingdom’s $650 billion economy.

John Sfakianakis, director of economic research at the Gulf Research Center in Riyadh, said women driving would give a significant boost to the Saudi economy.
Although difficult to quantify at this stage, the benefits could surpass $150 billion in terms of output gains per year over the medium to long term, Sfakianakis said.
“Just look at how many women will be able to be gainfully employed over time and the multiplier effects of employment on consumption. It’s a new era for Saudi Arabia.”
The move to allow women to drive, announced on Tuesday and set to be implemented by June, is the latest of a string of social and economic reforms in Saudi Arabia.

Analysts expect the move will produce a major economic dividend as more women are able to enter the workplace with the trickle-down impact providing a boost for everything from the insurance sector to banks. There are about 10 million women in the Kingdom over the age of 20.
“We see long-term support for growth in retailers and sellers of discretionary items, due to increased mobility and employment among women in Saudi Arabia,” said Mohammad Kamal, a director at Arqaam Capital.

Increasing female participation in the labor force is a central plank of the country’s Vision 2030 economic diversification blueprint.
“The decision to allow women to drive indicates that the authorities remain committed to implementing their ambitious reform agenda, despite an apparent slowing of economic reform momentum in recent months,” said Dubai-based Emirates NBD in a research paper.

Among the companies picked by Arqaam as potential beneficiaries is Fawaz Alhokair, one of the leading retail conglomerates in the country.
Tawuniya, the insurance group, is also set to cash in as the potential pool of insurable drivers doubles.

Other publicly traded companies picked by Arqaam include Budget Saudi Arabia, Saudi Marketing Co., Abdullah Al Othaim Markets, Al Rajhi Company for Cooperative Insurance and Axa.
Abu Dhabi-based NBAD Securities also sees Fawaz Alhokair as a potential winner as well as retailer Jarir.
“Other industry sectors that could benefit include banks, in the event that the demand for auto loans increase,” said Sanyalaksna Manibhandu, head of research at NBAD Securities in Abu Dhabi.

It is not all upside for the economy however as attention turns to the livelihoods of the hundreds of thousands of men employed as domestic drivers.
“Male chauffeurs may need to find new jobs as female passengers become drivers. If the decree merely leads to the replacement of a chauffeur by the passenger, auto dealers may not see demand increase as much as they would like,” added Manibhandu.
He expects demand for auto insurance to increase and that was reflected in the sharp rise among some publicly traded insurance companies on the Tadawul stock exchange on Wednesday.

Al Rajhi rose almost 7 percent on heavy volumes while car hire firm United International Transportation, also known as Budget Saudi Arabia, jumped 4 percent.
However the overall market retreated by about 0.1 percent as positive investor sentiment over women being allowed to drive was countered by concerns that Saudi Arabia may not be given emerging market status by index provider MSCI this month.
The economic empowerment of women in the Kingdom is a key part of that process.

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Civil Site Engineer’s Roles & Responsibilities

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A site engineer offers advice in the planning, co-ordination and supervision of technical aspects of construction projects. A site engineer’s role is vital to a construction project: they have a number of responsibilities including solving technical issues, providing advice, management and preparing reports.

Role and Responsibilities of a Civil Site Engineer

The site engineer should possess basic knowledge about the practical construction procedures in site, along with the details of how they are planned. This idea of planning and coordination will help him to have proper execution of the activities in the site with desired performance.

A site engineer is very essential for a construction project. The responsibilities of a site engineer are wide as he must provide sufficient advice and supervision when there are any technical issues, or for proper management and for the preparation of day to day reports of the construction works.

The responsibilities that is put on a site engineer in construction is mentioned briefly in below section:

1. Construction Site Responsibilities

The site engineer is the person who spends most of his time at the construction site compared with other managers or designers. Site engineers are updated daily about the coming day’s design and activities based on which he implements them at site.

The top members of the construction organization get a clear picture about the daily activities happening at the site through the site engineer.

2. Travelling

The site engineers are supposed to move from one site to another (based on the size of the project or number of projects) for any special needs. He must also be required to reach with the procurement of resources to get the materials as per the correct specifications if any discrepancies happen.

This means every sector of activities say its design, materials or execution, the site engineer has the role of advice.

3. Technical Activities

Site activities like establishment of the level and the survey control, which is required for the control of contracts must be performed by site engineer in required conditions. The works have to be set out as per the contract drawings. This requires checks at regular basis on the construction site.

The records maintained have to be accurate and they have to satisfy with the organizational and the legal requirements.

The site engineer has to face any unexpected difficulties raised from the technical side at any point of time. He must study the problem and resolve it in the most efficient manner as possible.

4. Preparation of Reports and Schedules

The site engineer is the one who have to ensure that the site have adequate resources to complete the tasks. This is conducted by having procurement schedules for the jobs carried out and liaise with the procurement department regarding the same.

A report on the future works to be carried out at site are prepared and produced by site engineers two weeks ahead. This is carried out in conjunction with the site agent.

The site engineer is responsible for keeping site diaries and the respective sheets for allocation.

5. Site Engineer for Health and Safety

For highly dangerous work site, the site engineer will take up the role of safety engineer. He has to ensure that the work carried out by the workers and other related activities are as per the safety regulation of the respective state or area.

Every construction organization must possess a safe working culture and practice. Its implementation and practice of following is supervised by the site engineers. There may be other safety, health officers for the organization, but ensuring safety is a common need.

Other responsibilities are to undergo construction activities that will promote the environmental compliance. Each work has to be carried out safely within the deadline.

6. Quality Assurance by Site Engineer

As we know, quality is a parameter that have to be kept in practice from the initial stage of planning to the end of the project. The major issues with design and documentation can be corrected during the construction by the site engineer based on advice from the structural engineers.

Any undesirable activities in construction brings high loss of quality and money. The site engineer assures quality by the following means:

  • Promoting the best construction practices
  • Undergo activities and practices that comply with the procedures of the company and the specification.
  • Assures the work is completed and delivered without any defect and delay
  • One must highlight value engineering opportunities

7. Communication and leadership duties

As the site engineer have to know the technical details from the above levels and make it in practice in the site, he must be efficient enough to coordinate the information that is communicated. He must take up the detail from the higher levels accurately and pass them to the below contractors, supervisors or labor workers. It not how efficiently you as a site engineer understand the idea, but it’s on how you convey it to your sub-workers. This will reflect to have the need for leadership quality to convey and make the workers do the work.

Proctor compaction test

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The Proctor compaction test is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density. The term Proctor is in honor of R. R. Proctor, who in 1933 showed that the dry density of a soil for a given compactive effort depends on the amount of water the soil contains during soil compaction. His original test is most commonly referred to as the standard Proctor compaction test; later on, his test was updated to create the modified Proctor compaction test.

These laboratory tests generally consist of compacting soil at known moisture content into a cylindrical mold of standard dimensions using a compactive effort of controlled magnitude. The soil is usually compacted into the mold to a certain amount of equal layers, each receiving a number of blows from a standard weighted hammer at a specified height. This process is then repeated for various moisture contents and the dry densities are determined for each. The graphical relationship of the dry density to moisture content is then plotted to establish the compaction curve. The maximum dry density is finally obtained from the peak point of the compaction curve and its corresponding moisture content, also known as the optimal moisture content.

The testing described is generally consistent with the American Society for Testing and Materials (ASTM) standards, and are similar to the American Association of State Highway and Transportation Officials (AASHTO) standards. Currently, the procedures and equipment details for the standard Proctor compaction test is designated by ASTM D698 and AASHTO T99. Also, the modified Proctor compaction test is designated by ASTM D1557 and AASHTO T180.

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Theory of Soil compaction

Compaction can be generally defined as the densification of soil by the removal of air and rearrangement of soil particles through the addition of mechanical energy. The energy exerted by compaction forces the soil to fill available voids, and the additional frictional forces between the soil particles improves the mechanical properties of the soil. Because a wide range of particles are needed in order to fill all available voids, well-graded soils tend to compact better than poorly graded soils.

The degree of compaction of a soil can be measured by its dry unit weight, γd. When water is added to the soil, it functions as a softening agent on the soil particles, causing them to slide between one another more easily. At first, the dry unit weight after compaction increases as the moisture content (ω) increases, but after the optimum moisture content (ωopt) percentage is exceeded, any added water will result in a reduction in dry unit weight because the pore water pressure (pressure of water in-between each soil particle) will be pushing the soil particles apart, decreasing the friction between them.