CIVIL ENGINEER'S PASSION

HDM-A Tool kit for Pavement Management

2011-12-13T19:26:00.000+06:00

HDM-4 is a computer software for Highway Development and Maintenance Management System. It is a decision making tool for checking the Engineering and Economic viability of the investments in road projects. The World Bank for the global use has developed it.

HDM-4 is the new windows version after HDM-III with incorporation of many new features so that it can be used in any locality of the world with any environmental and engineering situation.Sponsors, Coordinators and researchers.

Overview of HDM-4 use in Bangladesh
Bangladesh have been using HDM software since long. The previous version HDM-III was in use till 1999 after which the new version HDM-4 is now in use. The Roads and Highways Department (RHD) is the main user of this software. The first annual Maintenance programme for the year 1999-2000 was done using HDM-III. The next annual Maintenance programme for the financial year 2000-2001 was prepared using the new version HDM-4.

The consultants of a DFID financed Institutional Development Component (IDC) project is helping RHD since 1994 for the development of their technical skills to maintain their road network according to the modern maintenance management system. A new HDM Circle has been established in the Head Quarter to help attain this goal.

What Does HDM Do?

Project Analysis
Program Analysis
Strategic Analysis
Research, Policy and Regulation Analysis

Only describing the project analysis can be done for:

Maintenance of Existing roads

- Crack Sealing
- Pothole Patching
- Seal coat
- Single Bituminous Surface Dressing (SBSD)
- Double Bituminous Surface Dressing (DBSD)
- Carpeting
- Overlay
- Pavement strengthening

Improvement of existing roads
- Pavement reconstruction
- Pavement upgrading
- Road widening and geometric improvements
- Realignment

New construction
- Involves entirely new construction

Stage construction
- Planned improvements at fixed stages, say from HBB to Bituminous pavement.

Project evaluation
- Assessment of the performance of the completed project to see if objectives set out during appraisal have been met.

HDM-4 software System Architecture

Beside this HDM-4 also do the remain other three analysis as well.

Brief of The static pile load Test

2011-07-29T22:28:00.009+06:00

The static pile load test is the most common method for testing the capacity of a pile and it is also considered to be the best measure of foundation suitability to resist anticipated design loads.Procedures for conducting axial compressive load tests on piles are presented in ASTM D 1143 — Standard Test Method for Piles under Axial Compressive Load.

The pile load test can take a considerable amount of time and effort to properly set-up. Thus only one or two load tests are often recommended for a particular site.

Fig:-01

The location of the pile load tests should be at the most critical area of the site, such as where the bearing stratum is deepest or weakest. The first step involves driving or installing the pile to the desired depth. In Fig.01, the small arrows point to the concrete

Fig:-02

Fig:-03

piles that have been installed and are founded on the bearing strata. The next step is to install the anchor piles, which are used to hold the reaction frame in place and provide resistance to the load applied to the test piles. The most common type of pile load test to determine its vertical load capacity is the simple compression load test. A schematic set-up for this test is shown in Fig. 02 and includes the test pile, anchor piles, test beam, hydraulic jack, load cell, and dial gauges. Figure 03 shows an actual load test where the reaction frame has been installed on top of the anchor piles and the hydraulic loading jack is in place. A load cell is used to measure the force applied to the top of the pile. Dial gauges, such as shown in Fig.04, are used to record the vertical displacement of the piles during testing. As the load is applied to the pile, the deformation behavior of the pile is measured. The pile is often subjected to a vertical load that is at least two times the design value. In most cases, the objective is not to break the pile or load the pile until a bearing capacity failure occurs, but rather to confirm that the design end-bearing parameters used for the design of the piles are adequate. The advantage of this type of approach is that the piles that are load-tested can be left in-place and used as part of the foundation. Figure 05 presents the actual load test data for the pile load test shown.

Fig:-04

Fig:-05

Slump of Hydraulic Cement Concrete

2011-07-24T21:26:00.003+06:00

Slump test is one of the process to control quality of water cement ratio in field condition. It conforms ASTM Designation C 143. Now the procedure is discussed below.

Equipment and Materials

Frustum of a cone made of noncorrosive sheet metal, not less than 1.14 mm (0.045 inch) thick, 30.5 cm (12 inches) in height, with a 20.8-cm (8-inch) base, having a diameter at the top of 10.2 cm (4 inches), with foot pieces and handles as shown in Figure 1. There should also be a metal base plate with clamps that engages the foot pieces while the concrete is being poured into the slump cone and tamped with the tamping rod.

• Round steel tamping rod 16 mm (⅝ inch) in diameter, having the tamping end rounded to a hemispherical tip, approximately 60 cm (24 inches) long. Suitable, graduated metal scale approximately 25 cm (1 ft) in length.

Fig-1

Test Procedure
1. Dampen the slump cone and the metal base plate; then engage the slump cone with the base plate clamps. The base plate should rest on a level surface.

2. Fill the slump cone in three lifts, tamping each lift 25 times with the tamping rod, starting from the center and working toward the perimeter. The bottom lift should be rodded the full depth down to the base plate. For the two other lifts, the strokes of the tamping rod should penetrate into the underlying concrete layer. The top lift should remain heaped above the top of the slump cone after completing the rodding. Each of the three lifts should contain approximately an equal volume of concrete. Therefore, the bottom layer should have a rodded depth of about 7 cm (2½ inches) and the second lift to about 15 cm (6 inches).

3. Strike off the excess concrete with a screeding and rolling motion of the tamping rod.

4. Remove the cone carefully with a slow vertical motion without any rotational or lateral motion. The entire procedure from the time the fresh concrete is ready for testing to this point should be no more than five minutes. The time from the filling of the slump cone to determining the slump should be within 2½ minutes.

Fig -2

5. Set the slump cone in an inverted position next to the concrete and measure the distance to the top of the original center of the specimen as shown in Figure 2.

How concrete is mixed in concrete mixer

2011-07-22T23:11:00.005+06:00

In large and important works machine mixing is preferred. Figure shows a typical concrete mixer. Required quantities if sand and coarse aggregates are placed in the drum of the mixer. 4 to 5 rotations are made for dry mixing and then required quantity of cement is added and dry mixing is made with another 4 to 5 rotations. Water is gradually added and drum is rotated for 2 to 3 minutes during which period it makes about 50 rotations. At this stage uniform and homogeneous mix is obtained.

Environment Impact Assessment (EIA)

2011-07-20T22:20:00.007+06:00

Environment Impact Assessment (EIA) is adecision making tool to predict the effect of activity/project on the environment,compare various alternatives for a project and identify best combination of economic, environmental and social costs and benefits.

Firstly this study procedure originated in the US in the late 70s and then spread to the developed world. It reached the developing world in the 80s that funding agencies like World Bank/ ADB adopted it in late 80s. Originally focused on environment alone but later on social and economic aspects added to its scope of study.

EIA have Three core values:

1. Integrity

Should be fair, objective, unbiased and balanced

2. Utility

Provide balanced and credible information for decision-making

3. Sustainability

Result in environmental safeguards.

Generic steps of EIA

Integration of EIA in project cycle
(To see bigger picture click on the picture)

Pre feasibility stage

•Screening

ØDecide the requirement of EIA

•Scoping

ØIdentifying significant impact areas and defining terms of reference for the EIA

Feasibility stage

•Baseline data collection

ØCollecting all the information required for an impact assessment

•Impact assessment

ØConducting an extensive environment impact assessment using all available information

•

Design and engineering stage

•Mitigation and environment management plan

ØDesigning a mitigation and environment management plan for reducing impacts

Implementation and post monitoring stage

ØImplementation of the environment management plan and monitoring of impact

If erosion occurs somewhere

2011-07-18T00:11:00.005+06:00

If erosion occurs somewhere, five main options are available

1 Do nothing
If erosion causes no problems, this is the favourite option.

2 Take away the cause of the problems
This is theoretically always the best thing to do, but since you need to know what the cause is and you have to be able to do something about it, it is not always feasible. A solution that comes close is to build groynes along a coast where the erosion is caused by long-shore transport. If the erosion is caused by cross-shore transport, groynes are useless!

3 Supply sediment
This may seem a poor solution, since it cures nothing and it may have to go on forever, but it is often a good measure. It is very flexible and fits very well in environment strategies.Whether this is the right option depends mainly on costs and risks, since sediment is usually supplied with intervals of several years. For coasts and rivers this "soft" solution can be an attractive alternative. Further treatment of this option is part of morphological studies.

4 Reduce the loads
This can be done by constructing a breakwater in front of an eroding coast. Only the design of such a breakwater is capable.

5 Increase the strength
This the "hard" solution. It is not a very flexible option and it can sometimes lead to more erosion in adjacent areas. In many cases however, especially when there is a lot of pressure to preserve the available space, it is the only solution.

What is Civil Engineering?

2011-06-27T20:36:00.003+06:00

Civil engineering is a professional engineering discipline that deals with the design, construction and maintenance of the physical and naturally built environment, including works such as bridges, roads, canals, dams and buildings. Civil engineering is the oldest engineering discipline after military engineering,^[4] and it was defined to distinguish non-military engineering from military engineering.^[5] It is traditionally
broken into several sub-disciplines including environmental engineering; geotechnical engineering, structural engineering, transportation engineering, municipal or urban engineering, water resources engineering, materials engineering, coastal engineering,^[4] surveying, and construction engineering.Civil engineering takes place on all levels: in the public sector from municipal through to federal levels, and in the private sector from individual homeowners through to international companies.