چكيده لاتين
Soil as one of the oldest and most widely used building materials, has regained attention due to its unique characteristics, including its natural composition and recyclability.
Among various types of earthen structures, rammed earth offers significant advantages over other methods due to its density and structural integrity. However, the primary drawback of earthen structures is their low tensile strength. Therefore, this study investigates the structural behavior of rammed earth arches and explores enhancing their capacity using jute fabric as a strengthening material. This choice is motivated by juteʹs high tensile strength, lightweight, natural fiber composition, and compatibility with soil.
The research employs finite element software (ANSYS) and the Drucker-Prager failure criterion to assess the capacity of both unreinforced and reinforced Persian arches. The arches analysed include semi-circular, pointed, and four-centred types, each of pointed arch and four-centred arch has three types: drop, ordinary, and raised. The geometric behaviour of these arches is also examined based on thickness to span ratios of 0.122, 0.183, and 0.244. The loading scenarios considered in this research include linear loads at mid-span, linear loads at one-quarter span, support rotation, support settlement, and earthquakes.
Strrengthening strategies are classified into four types based on their application: strengthening only at the intrados, only at the extrados, simultaneous strengthening at the intrados and extrados, and wrapped strengthening. Each method can cover either the entire length or a part of the arch to enhance tensile resistance, structural cohesion, and stress distribution.
In this study, two samples of unreinforced and reinforced rammed earth arches were simultaneously tested under a linear load at the center of the span. The analysis was conducted using ANSYS software, comparing the failure load and displacements at two points: the midpoint of the span and at a 45º angle of the arch. The results of this comparison indicated that the differences in failure load and displacement in this validation method were 3% and 7%, respectively.
Results show that reducing the thickness to span ratio significantly improves the effectiveness of the strengthening. The most effective scenario involves a thickness to span ratio of 0.122 with strengthening. For linear loads, strengthening at the intrados of the arch proves to be the most effective. In four-centred arches, entire length strengthening at the intrados increases load bearing capacity by up to 97%, whereas in pointed arches, localised intrados strengthening improves load bearing capacity by 52%.
In the case of base settlement and earthquake loading, entire length strengthening simultaneously at the intrados and extrados, and wrapped strengthening are the most effective. These configurations increase load bearing capacity by 70% and 66%, respectively.
