Jiangsu Provincial Transportation Planning and Design Institute is committed to providing planning, consulting, surveying, design, scientific research, and testing services for roads, bridges, tunnels, railways, tracks, ports, waterways, ship locks, industrial and civil buildings, environments, landscapes, and intelligent transportation
Engineering consulting services in related fields such as testing, supervision, and project management. Having Class A design qualifications in the highway industry, water transportation industry, and municipal industry (roads, bridges, rail transit, urban tunnels)
Class A qualifications for design in the construction industry, comprehensive engineering survey, engineering consulting, highway engineering and mechanical and electrical engineering supervision, comprehensive highway engineering, special highway engineering bridge and tunnel engineering, water transportation engineering materials
Qualification for Class A testing and inspection of water transport engineering structures. In 2007, independently undertook the design and construction of the dehumidification system for the main cable of the Taizhou Yangtze River Bridge in Jiangsu Province.

The bridge is located between Taizhou, Zhenjiang, and Changzhou in Jiangsu Province, and is an important river crossing project in the expressway network of Jiangsu Province. Including the main bridge, Jiajiang Bridge, and corresponding approach bridge connection projects, with a total length of 62.088KM and a total project investment of 93.7

Billion yuan, with a total project duration of 5 and a half years. Based on the characteristics of the riverbed section at the bridge site and the natural environmental conditions at the bridge site, the design selection of the main bridge is based on the fundamental starting point of ensuring navigation, utilizing the Yangtze River's submerged shoreline, and constructing a conservation oriented project

The three tower two main span suspension bridge scheme has been developed, with a span arrangement of 390+2X1080+390m, and is a kilometer level three tower two main span suspension bridge.

The suspension bridge has a beautiful shape and a large spanning capacity, making it a structural form of large-span and extra long span bridges. Suspension bridges are mainly composed of main towers, anchorages, saddles, main cables, suspension cables, bridge deck bearing beams, and accessories, with a design life of generally 100 years.
The main cable is one of the main load-bearing components of a suspension bridge and cannot be replaced. Therefore, it is called the "lifeline" of a suspension bridge. Due to long-term exposure to the atmospheric environment and various adverse environmental erosion, water vapor and rainwater in the air
And the invasion of corrosive gases leads to the easy corrosion of the main cable steel wire. Corrosion reduces the effective cable area and strength, endangering the safety of suspension bridges. Jiangsu Provincial Transportation Planning and Design Institute realized the seriousness of this problem and began to

Find an effective solution to prevent corrosion of the main cable. They have borrowed advanced technology from abroad and used the main cable dehumidification system of suspension bridges in China.

The main cable dehumidification system can prevent the corrosion of the main cable steel wire, improve the service life of the main cable steel wire, and thus enhance the service life of the entire bridge. It is the development direction of the main cable protection technology for suspension bridges. The purpose of the main cable dehumidification system is to reduce the relative humidity inside the main cable, keeping it in a relatively enclosed and dry environment to prevent rusting of the steel wires inside the main cable. The main cable of Taizhou Yangtze River Highway Bridge adopts prefabricated parallel steel wire strands. Each main cable consists of 169 strands, and each strand is composed of 91 galvanized high-strength steel wires with a diameter of 5.2mm, with a gap of about 20%. The outer surface of the main cable is equipped with a sealed sheath layer. The main cable dehumidification system injects dry air into the gap of the main cable steel wire through the air supply pipe and air supply hood. The dry air flows in the gap of the main cable, reducing the humidity of the air in the gap. Finally, the dry air becomes humid air and is discharged from the exhaust hood. The main cable sheath layer isolates the dry internal environment of the main cable from the external atmosphere, maintaining a dry state inside the main cable. The workflow of the main cable dehumidification system is as follows: coarse filtration of air → fine filtration treatment → dehumidifier dehumidification → high-pressure fan air supply → cooling → air supply through the air supply pipe → air supply through the air supply hood → dehumidification inside the main cable → exhaust hood exhaust (see Figure 1 for the workflow of the main cable dehumidification system).

Challenge

●Long term exposure to the atmospheric environment and exposure to various adverse environmental erosion. The corrosive substances floating in the air combine with water vapor to jointly cause and accelerate the corrosion of metals.

●Stability and ease of operation. Due to the length and height of the main cable, as well as the special location of the monitoring points, maintenance is difficult and requires highly reliable and stable measuring instruments that are easy to operate and maintain. Management personnel can manage various monitoring points through the system
The working condition.

Solution

●The main cable dehumidification system adopts a distributed two-level monitoring mode of "monitoring center on-site main controller". Sensor data collection network. The dehumidification system of the main cable of Taizhou Bridge is monitored by temperature and humidity sensors at 48 points.

●Install a temperature and humidity sensor at the filter to detect the temperature and humidity of the inhaled air.

●Install a temperature sensor for the aftercooler.

●Install temperature and humidity sensors at the air supply hood to monitor the temperature and humidity of the air supply at the hood.

●Install a temperature and humidity sensor at the exhaust hood to measure the temperature and humidity of the air supply at the hood.

benefit

For industrial applications in harsh environments, the IP65 corrosion-resistant housing maintains stable performance in harsh environments.

Vaisala HUMICAP ® Sensors have good accuracy and stability.

Real time data display, abnormal alerts. Display measurement trends and historical records over four years.

Data protection: Will not cause data loss, including network failures or power outages. The battery has a minimum lifespan of 5 years.

High stability: Two years ± 2% stability, ensuring stable operation of the system.

According to customer requirements, follow-up verification and calibration services can be provided.

We chose Vaisala HMT330 as the temperature and humidity monitoring system for the main cable dehumidification system of Taizhou Bridge because Vaisala sensors have reliable quality and strong stability. The dehumidification process is crucial for the maintenance of the main cable
Very important, Vaisala temperature and humidity sensors are a crucial part of the entire dehumidification system operation! Due to the outdoor installation of sensors, the requirements for adapting to the environment are very strict. If stability cannot be achieved, manual inspection and maintenance are necessary

The cost is enormous, so this is crucial. ”

——Jiangsu Provincial Transportation Planning and Design Institute

Project Manager Zhu Dongqing

Solution

During the bidding process for the humidity monitoring system, several suppliers were evaluated. Through selection, the Vaisala HMT330 series temperature and humidity sensor stood out. HMT330 series HUMICAP ® Temperature and humidity transmitter design can be used for harsh conditions
The industrial application of engraving meets a wide range of user needs with good accuracy and stability. The reason why we chose Vaisala is because we value the high precision and good stability of Vaisala products! The corrosive environment in which suspension bridges are located is atmospheric, and outdoors

Under strict conditions, product stability is crucial! ”Zhu Dongqing, the project manager of Jiangsu Provincial Transportation Planning and Design Institute, admitted frankly.

Reliability: Industrial Solutions

At present, the HMT330 temperature and humidity sensor is performing well in application, monitoring a total of 48 temperature and humidity sensors installed at the air outlet. ”With HMT330, managers at all levels of bridge maintenance units can view important key information in real time
Region, view historical data for analysis to ensure more scientific maintenance of bridge main cables.

Related Products

(Industrial temperature and humidity instrument series HMT330 is used for demanding temperature and humidity measurement)

Vaisala HUMICAP for measuring humidity in harsh environments using reliable instruments ® The industrial temperature and humidity transmitter series HMT330 is designed for demanding industrial applications that require stable measurement and extensive customization.

Please be informed that the HMT330 series is gradually being discontinued. It will be replaced by Indigo series products. Please do not purchase HMT330 for new projects. Welcome to use Indigo data processing units and probes, which are also designed to meet demanding application conditions
And design.

Do you like our HMT330 series? Then you will definitely fall in love with Vaisala Indigo.

The new Indigo platform adopts the same measurement technology as its predecessor HMT330 series. The important and widely expected feature of the Indigo platform is the interchangeability of intelligent probes. Nowadays, smart probes are equipped with many functions that are traditionally located inside the transmitter, allowing for on-site replacement and cross functional configuration.