On September 26, the Lijia Jialing River Bridge, Caijia Jialing River Bridge, Shuitu Jialing River Bridge (Shuitu New City Bridge) and Tuzhu Tunnel were all completed at the same time, and will officially open to vehicle traffic at midnight on September 29.

Among them, the Lijia Jialing River Bridge and the Shuitu New City Bridge were both designed by T.Y. Lin International. What are their design highlights? Let's hear what the designers have to say.

Lai Yaping, chief designer of the Lijia Jialing River Bridge and deputy chief engineer of bridge engineering at T.Y. Lin International (China), introduced that the Lijia Jialing River Bridge is a controlling node project of the second east-west expressway in Chongqing, connecting Chongqing's Liangjiang New Area and Shapingba District.

The bridge has a total length of 785 m, a main span of 245 m, eight lanes in both directions, and a twin-deck arrangement, with each deck 18 m wide and a design speed of 80 km/h. Taking into account factors such as terrain conditions, navigation requirements, structural performance and landscape features, the project adopts a prestressed concrete deck-type beam-arch combined rigid frame plus variable cross-section continuous beam composite bridge scheme.

Through analysis of the surrounding environment and regional culture of the bridge site, combined with the bridge's simple and grand shape, smooth lines and resemblance to a flying swallow with spread wings, the bridge's landscape design was determined with the theme of "swallows flying together."

In the bridge's landscape design, structural system innovation was comprehensively considered, and concise line elements were applied to shape the bridge, creating a simple yet not simplistic image style; the outer surface of the bridge body uses a light gray-white coating, plain and elegant, blending harmoniously with the surrounding environment; the pedestrian guardrail is a composite guardrail of cast stone and steel structure, with modeling elements consistent with the overall shape of the bridge, and serves as a carrier for displaying Chongqing's main urban landmark image.

The Lijia Jialing River Bridge fully considers the impact of the bridge type scheme on the regional spatial environment of Chongqing, a typical landscape city, and controls the bridge's form and volume in combination with the skyline of mountains and buildings, ensuring that the bridge integrates into the environment and forms an organic whole with it.

In the overall modeling design, based on the environmental characteristics of distant continuous mountains and nearby rippling water, the deck-type beam-arch combined form is adopted. The bridge deck is flat, and the bottom edge lines of the main span center and side span beam sections, as well as the bottom edge line of the beam-arch combined section, are consistent with the bottom edge line of the lower-chord box arch, presenting an arch shape in elevation and highlighting a graceful curved form.

There are no spandrel columns in the beam-arch triangular area, which gives it both the simplicity of a beam bridge and the beauty of an arch bridge. The form naturally transitions into the landscape and complements the environment. It fully demonstrates the bridge's "beauty of form," "beauty of crossing" and "beauty of strength," adding a new bridge type to Chongqing, the "City of Bridges."

As an extra-large river-crossing urban bridge in Chongqing's main urban area, in addition to meeting the traffic function of the second east-west expressway, the bridge also strives to be novel, unique and beautiful, fully displaying the characteristics and heritage of "bridge capital culture," creating a beautiful scene in which "bridges" and "mountains, water and the city" enhance each other, and better presenting regional cultural connotations and the city's new image.

Meng Jie, designer of the Shuitu New City Bridge and assistant general manager of the Bridge Division of T.Y. Lin International (China), introduced that the Shuitu New City Bridge spans the Jialing River, connecting Caijia Jiarui Avenue in the south and Shuitu Yunhan Avenue in the north. It is an important heavy-traffic artery connecting the Shuitu and Caijia areas and the most convenient channel linking Shuitu to the expressway network. The construction of the project will greatly shorten urban space, solve urban traffic problems, and promote the development and construction of the Shuitu and Caijia areas.

The Shuitu New City Bridge has a total length of 956 m. The main river-crossing bridge is a cable-stayed bridge with a main span of 388 m, high and low pylons, and steel-concrete composite girders. The bridge is 31.8 m wide and adopts a rigid frame system with fixed pylon-girder connections.

The bridge pylons are concise, sharp and full of modernity. The pylons uniquely adopt a form of two pylon legs without cross beams, providing an open view from the bridge deck, and the overall bridge is grand and imposing.

The main bridge adopts steel-concrete composite girder technology. The steel girder part uses an I-shaped longitudinal and transverse girder system, combined with concrete slabs through shear studs to bear loads together. This technology can fully leverage the advantages of both materials and is economically reasonable; the main girder adopts factory prefabrication and on-site installation, greatly reducing on-site cast-in-place work and being low-carbon and environmentally friendly; because the bridge deck uses a concrete structure, it also avoids the problem of poor durability of steel bridge deck pavement, reducing later maintenance and management costs for the bridge deck. Therefore, the completion of this type of bridge is an important lever for practicing the "dual carbon" goal in the infrastructure field.

The pylons adopt a form of two pylon legs without cross beams, measuring 128 m above the bridge deck and 73 m below it, with a total height of 201 m. Through reasonable changes in cross-section form, the upper pylon column makes the section centroid coplanar with the stay cables, ensuring that the pylon column remains under axial compression under dead load. The completion of the Shuitu New City Bridge will also set a record for this type of bridge pylon in the bridge industry.

The western section of Chongqing's second east-west expressway starts in Western (Chongqing) Science City and ends in Liangjiang New Area, crossing Shapingba District, Beibei District and Liangjiang New Area; the Chongqing Caijia Jialing River Bridge project starts in Caijia, Beibei District in the north and connects to Lijia, Liangjiang New Area in the south; the Chongqing Shuitu Jialing River Bridge project starts in Shuitu, Liangjiang New Area in the north and connects to Caijia, Beibei District in the south.

After the "three bridges and one tunnel" officially open to traffic, they will connect clusters such as Tuzhu, Jingkou, Lijia, Caijia and Shuitu, further opening up the westward passage of the main urban area and achieving rapid access from Western (Chongqing) Science City to Liangjiang New Area. From then on, the Jialing River will have three more river crossings, and Zhongliang Mountain will have one more mountain tunnel.