Abstract

The Libeň bridge in Prague is a cultural and technical heritage of concrete construction of the beginning from the twentieth century. The bridge was designed by architect Pavel Janák, the founder of cubism in architecture. According to experts, the Libeň bridge is the only example of cubist morphology application on the bridge structure. Evaluation of Libeň bridge structural condition is an up-to-date topic leading to decision whether this bridge should be repaired or replaced by a new bridge. This article deals with the static and dynamic load testing in comparison with following creation and validation of the FEA model for load carrying capacity assessment of the Libeň Bridge and possible way of reconstruction. Paper deals with crucial procedures for FEA model validation of this backfilled arched concrete structure with a focus on the static characteristic of the structure. Article deals with reconstruction of the vault part of the Libeň Bridge using R-UHPFRC in terms of static operation. It focuses on the two basic problems of the bridge, the solution to increase the bearing capacity of the vault arches and to increase the bearing capacity of the foundations under pillars. The concept of repair is based on extensive diagnostic surveys conducted in 2017. The concept of structural enhancement is based on adding new thin layer of R-UHPFRC (reinforced, ultra-high performance concrete) on the upper vault surface. Concrete bridge structures are exposed to extreme effects of aggressive environmental influences, especially chlorides, which leads to damaging of most exposed bridge components a long time before their service life. UHPFRC material is suitable for repairs of these structures and especially due to its impermeability and high resistance.

Abstract

Ancient Caesarea has founded in the years 25-10 BC and named after Emperor Augustus. Throughout history, from the early Roman until the Byzantine period, Caesarea was a major city and one of the largest and most important port cities in the Mediterranean. During the Byzantine period, the city encompassed an area three times larger than that delimited by the Herodian wall and became an important center of Christianity. The monumental stairs led to the Byzantine Octagonal Church built upon giant arch above the remains of the enormous Roman stairs of Augustus temple. Stairs led a large number of people from the vast harbor, to the Temple platform. The Byzantine arch located 17 meters from the ancient quay, is 8 meters width and 4-meter long, built with specific technology from local sandstone named Kurkar. The arch fall after the Byzantine period and the staircases severely damaged due to the long exposure of almost 1500 years and environmental conditions such as capillary rise, daily winds carrying sand, high temperature, moisture, salts, and deliberate destruction, for instance, stones robber and collapse parts from the wall. The characteristics of the Kurkar with sustained deterioration and this environmental condition have led to different conservation problems, at various levels of severity erosion, the disintegration in both bonding materials and stones. The conservation measures' purpose is to stop the ongoing weathering process and prevent a deterioration state of the staircases, to restore the arch and stabilize the structure of the stairs to carry 48 tons of the restore arch. The findings of the project show that a suitable solution to ensure effective and sustainable protection of complicated staircases structure from destruction and various weathering condition to carry new massive arch depends on understanding the ancient application of building technologies and techniques, the use of original bonding material, integrated monitoring, and ongoing maintenance.