How to Build a Cable-Stayed Bridge

According to ehow.com

Although a cable-stayed bridge may look like a suspension bridge at first glance, it carries the load of the roadway in a different way. While the cables of a suspension bridge carry its load, the pillars carry the load in a cable-stayed bridge. The cables are merely a redirection of that load bearing. Here is how to build a cable-stayed bridge.

The first phase: Design and Placement

Step 1: Study the area. You may need to do a traffic study to determine the best place to build your bridge. In most cases you will be crossing a wide area such as a large river or small bay. Bore holes to determine the makeup of the soil under the waterway.

Step 2: Determine the materials you will use for construction. Steel cables and pillars with poured concrete bases are most commonly used.

Step 3: Obtain survey data and draw construction drawings of the bridge. This will require a team of drafters, designers and structural engineers. The structural engineer will need to stamp the drawings to be approved by your local governing body.

The second phase: Estimation and Bidding

Step 1: Estimate the cost of the bridge building project. Obtain a copy of the construction drawings from the designing engineer and determine how much each item will cost in labor as well as materials.

Step 2: Complete your itemized bid to build the bridge. Make sure you take into account all specifications and details, including typical section details and utility restoration.

Step 3: Submit your bid to your governing authority. Most of the time, these are closed bids and the lowest bidder with the most complete itemization will win the bid.

The third phase: Bridge Construction

Step 1:
Build the concrete forms for the pillars. These are placed in the waterway, connected and sealed to make a watertight form. Pump out the water and excavate to a solid base.

Step 2:Pour the pillars and place anchor-bolts or other steel connectors into the concrete. This is where the tall steel poles will be placed.

Step 3: Set your pre-cast towers on your concrete base and secure by the method detailed by the engineer. This will require a large crane and some other heavy construction equipment.

Step 4: Thread cables through the pillars according to the engineer's specifications. Attach these to the decking as each bridge section is built, cantilever style. Many cable-stayed bridge designs allow for an adjustment to the tension on the cables, so one section is not supporting more weight than its neighboring cables, thereby weakening that cable and possibly causing catastrophic failure.

Step 5: Prepare the terminal ends of the bridge. In building a cable-stayed bridge, the terminal ends are where the roadway meets the land. These ends are where the greatest tension on the cables are and don't need as much reinforcement as a beam bridge, for example. In fact, depending on the stresses, you might be "pulling down" the roadway, instead of "holding it up."

Step 6: Pave the decking and enjoy your new cable-stayed bridge.

HCMC addresses dilemmas in proposed fly-overs

According to dtinews.vn

In the early 21st Century, Ho Chi Minh City planned to build fly-over routes with an aim of resolving traffic congestion. In ten years, this plan has never left the paper.

The idea had become an objective in 2005 which was a part of the Ho Chi Minh City’s transportation development planning up to 2020. Accordingly, the city will finish construction of the four fly-over routes in 2020 which will connect each other.

The Prime Minister previously approved the proposal by issuing Decision No. 101/QĐ-TTg on January 22, 2007. After that, the city announced the planning in public and called for investors to bid for building the four routes which are considered as dragons in the sky connecting areas and lessening traffic pressure in the city.

The plan drew the attention of many international organisations. On December 6, 2007, GS E&C Company signed a memorandum of understanding with the city about the investment feasibility of constructing the first route under a build-operate-transfer contract. But in February 2009, the company cancelled their proposal. According to the People’s Committee of Ho Chi Minh City, the reason was because they had financial difficulties and wanted to focus on the project connecting Tan Son Nhat, Binh Loi and the Outer road belt.

The feasibility of the 2nd route was studied by Wijaya Baru Global Berhad Company (Malaysia) and the 4th route was taken care of by the General Construction Company No 1 under the Ministry of Construction in February 2008.

However, to date, the feasibility report of the 2nd route has been made and the proposal of the 4th route has been finished.

In addition, the 2nd and 4th routes face difficulties in planning so they need to be postponed and wait for guidelines from the Government.According to investors, the feasibility of the 2nd route is not high because it will effect the Hoa Hung Railway Station planning. Moreover, the route will cross over highly populated areas so site clearance expenditure will be very large.

The 4th route also faces the same dilemma of site clearance expenditures. In addition, it will effect planned areas that it would cross through.

The 3rd route hasn’t really received any attention.

Investors are working on researching other route directions which would be more feasible to submit to the city. The Government will decide direction changing of the 2nd and 4th routes proposed by the committee.

The Prime Minister has assigned the Ministry of Construction to study the proposal. After finishing, they will submit a report to the Government.

Approved fly-over routes

+ Approved route 1: starting from intersection of Cong Hoa Road, Bui Thi Xuan, Nhieu Loc-Thi Nghe Canal and ends at Nguyen Huu Canh Road.

+ Approved route 2: starting from junction point with the 1st route and To Hien Thanh Road, then Lu Gia, Binh Thoi, Lac Long Quan, Road No. 3 and Belt Road No. 2.

+ Approved route 3: starting from junction point with the 2nd route and To Hien Thanh Road, then Le Hong Phong, Ly Thai To, Nguyen Van Cu, Le Van Luong and Nguyen Van Linh.

+ Approved route 4: starting from intersection of Binh Phuoc, National Road No. 13, crosses over Sai Gon River, Vuon Lai Road, Nguyen Xi, Dinh Bo Linh, Dien Bien Phu and meets the 1st route.

Alternate Proposed routes

+ Proposed route 2: starting from the junction point with the 1st route at Bridge No. 5 of Nhieu Loc-Thi Nghe canel, Alley No.657 of Cach Mang Thang 8 Road, Bac Hai, Alley No.2 of Thien Phuoc, Alley No.654 of Au Co, Lac Long Quang, Dam Sen Park then Bau Trau small canal, Chien Luoc, Ma Lo, Huong Lo No.2 and National Road 1A.

+ Proposed route 4: starting from Vuon Lai Road, crossing Vam Thuat River, Lang small canal then meets with the South Northern railway at Den Bridge, Phan Chu Trinh, then crosses Cau Bong small canal, Dien Bien Phu and meets with the 1st route.

The famous tunnel in the world

1. The Straits of Manche Tunnel

Lieing under the Strait of Manche, this tunnel is the second length tunnel in the world with 50.5 km length. It also has the longest sinking part in the world with 37.9 km length. The deepest point of it is 75 m. It began in 1988 and finished in1994. It links England with France.

2. The Seikan tunnel, Japan

This tunnel is the longest rail tunnel in the world with 53.58 km length. The sinking part has 23.3 km length. It lie under the Strait of Tsugaru and linking Honshu Island with Hokkaido island. This tunnel began in 1971 and finished in 1988. It has 52 km length of continuous railway and the first two railway stations in the world which were built under sea.

3.The Gotthard tunnel, Switzerland

This tunnel is being in the construction phase. It was designed with 57 km length and in the near future, it will be the longest tunnel in the world in 2018. One special, it goes through the Alsp moutain which is considered as a barrier between the North and the South of Europe. It links Zurich city of Switzerland with Milan city of Italy. This is a project which has huge size with the enormous numbers: More 2000 worker work 24h per day and 365 days per year. The cost booms from $ 8 billion up to $ 15 billion.

4. The Tunnel of drug at the boundary of American and Mexico

This tunnel is the secret road which smugglers used to transport drug passing the boudary of American and Mexico. The tourist will feel accidentally because it was built sophisticatedly. It was equiped lighting system, wind system, water supplying system and even elevator. It was hided at the back of radiators and toilets, etc. Both ceiling and wall were paved by wood.

5. The Tokyo bay Tunnel, Japan

This tunnel began in 1989 and finished in 1997. This is a complex construction with 15.1 km of total length. It include 9.5 km of tunnel length, 4.4 km of bridge length and 2 man-made islands. The deepest point of tunnel is 60. There is a interest of the islands, that is it has a big car park and a resort where tourist can rest when they do sightseeing the bay.

6. The Chesapeake Bay bridge and tunnel , American

This construction was completed in 1964. Its total cost is $ 2 Million. It links the south - east of Virginia with Delmarva peninsula. Total complex construction has 2 high bridges, 2 low bridges and 2 parallel tunnels with 28 km of length. The most of all is over water level, it was supported by more 5000 posts, the remainder is more 3km of tunnel length. The construction also has man-made islands along 2 tunnels. On the islands, there are hotels, souvenir stores and car parks that service tourist to relax and to enjoy the view. It is the most excellent construction achievement of American in 1965 and It also is one of the seven construction wonder of modern world.

The cable-stay bridges in Viet Nam

Now, there are six cable-stay bridges in Viet Nam. They were built by modern construction technology. They are Phu My Bridge in HCM city, My Thuan bridge in Tien Giang province, Binh bridge in Hai Phong city, Bai Chay bridge in Ha Long city ( Quang Ninh Province), Rach Mieu bridge in Ben Tre province and Thuan Phuoc bridge in Da Nang city.

My Thuan bridge is the first cable-stay bridge in Viet Nam. It links Tien Giang province with Vinh Long province in Nine dragon river delta. It began in July,1997 and finished in May,2000. Its length is 1535 m in there cable-stay span's length is 350m. Its width is 23.66 m and its height is116.5 m. It has two H shape piers which is art figure. Its cost is $ 90.86 Australia.

The next cable-stay bridge is Binh bridge. It began in september, 2002 and finished in May,2005. It was built from 1.3 km away Binh ferry. It repaired traffic jam condition at Binh ferry and help to develop a new urban of Hai Phong city in the north of Cam river area. It has 1280 m length, 22.5 m width and 101.6 m height. Its cost is JPY 8.02 billion and VND 141.5 billion.

The next cable-stay bridge is the first and longest one side cable-stay bridge in Viet Nam. It cross Cua Luc river in Ha Long city. It began in May,2003 and finished in december, 2006. Its length is 903m in there main span - cable-stay span has 435 m length. It has 25.3 m width and 130 m height. Its highlight point is one side cable-stay. It also is one of the longest main span in the world. The road connect to the main bridge has 5 km length and it has 8 sub bridge with total length is 1172 m. Its cost is VND 2140 billion.

The next cable-stay bridge is the first " made in Viet Nam" bridge, it is Rach Mieu Bridge. It began in April,2002 and finished in January, 2009. It links Tien Giang province with Ben Tre province in Nine dragon river delta. The main bridge has two bridges with total 2.86 km length. Main span is cable-stay span with 270 m length. It has from 12 to 15 m width and 117 m height. Its cost is VND 1400 billion. Its special: it is the first cable-stay bridge which was desgned and duilt by Vietnamese ( SVL firm of Switzerland supported technology )

The next cable-stay bridge is Thuan Phuoc birdge, the longest cable-stayed bridge in Viet Nam. It coss Han river. It links Hai Chau district with Son Tra peninsula in Da Nang city. It began in January, 2003 and finished in 2009. Its total invested capital revised up to VND1 trillion. Its length is 1.85 km and its width is 18 m. Its special is the longest main span in Viet Nam with 655 m.

The last cable-stay bridge is Phu My bridge which began in Mar, 2007 and finished in Dec, 2009. It cross Sai Gon river. It was built by private budget. It was invested by BOT Phu My bridge JSC with budget of company with out national budget. Its total investment is VND 2500 billion. The bridge has 2100 m length, 27.5 m width and 140 m height. The main span is 380m length.

This list is the bridges which was finished. There are other cable-stay bridges which is building. In there, Can Tho bridge is the first bridge which will have finished by next time.

Seven mile bridge

Seven mile bridge is one of the longest bridge in the world. It links the city of Marathon in the Middle Keys of Florida to Little Duck Key in the Lower Keys of Florida. It is overseas bridge and it also is called overseas highway. It began in 1979 and finished in 1982. Total its cost is about $45 million. Its length is 10.93 km.

Civil engineering

Who are civil engineerings? What do they do?

Civil engineerings are who graduated at some tech universities such as Architect universities, construction universities, comunication and transport universities, hydrology universities, electricity universities .etc. All of them have a general point that is their job relate construction work. They may be designer, employer, contractor, project management or consultancy .etc. They design, build or maintain many other constructions such as road, rail, bridge, port, building, stadium, factory .etc.