The western iwan of the Takht-e Soleymān is one of the most important buildings in this area. Based on some accounts, this iwan was constructed during the Sāssānid period and the Ilkhanate kings restored it after 700 years. This unique structure is statically unstable and needs strengthening. To this end, becoming familiar with the building materials and their use in this structure are important. The aim of this research is examining the building materials used in the western iwan of Takht-e Soleymān in the two significant architectural periods of Takht-e Soleymān (Sāssānid and Ilkhānid), with focus on the use of the building materials and their positioning. This research has been conducted using the field study method. The research results show that the building materials used in the construction of the western iwan are stone, brick, and half baked, half worked plaster. Smoothed stone is used in the first architectural period following the style of all the other structures built in the area. Using the excavations near the iwan abutment, and comparing with the northern and sudden supports, it was revealed that the abutment of the iwan are rows of smoothed stone in stretcher bond formation. The main body of the abutment, up to the brickwork, is also built from smoothed stone to a height of 5.2 meters. The remarkable point in this regard is the gradual change of the stretcher brickwork to the stretcher-header brickwork (similar to the method used in the perimeter wall). This is done in such a way that the lower rows are stretcher brickwork and the higher rows are stretcher header. On the top part and the top of the smoothed masonry, square bricks are used with sides of 29 centimetres and thickness of 7 centimetres. The brickwork is stretcher with a one third overlap. By observing the similar buildings to the iwan in the area, it seems that the barrel vault was also made of bricks. The mortar used in the construction of stone and brick part in this architectural period was half baked, half worked plaster. In the second architectural period in which the Ilkhanate reconstructed the parts fallen down since the first architectural period, stone rubble and plaster were the main building materials. The top parts and some of the parts which had been separated from the body of the iwan as a whole layer were reconstructed. A cover of ornamental tiles [qashani] and from the inside and muqarnas in the apex of the iwan. The stone rubble used in the western iwan in this period was the remnants of the building materials used in the first period which differed in dimension and was placed in horizontal rows. The impost of the vault is evident by a 10 cm projection of the building materials. The mortar used is half baked half worked plaster as was revealed using chemical analysis. Another remarkable element in this period is the qashani covering the inside of the abutments which is a remarkable ornamental element of the Ilkhanate period in this location. The eastern front and the sides of the iwan entrance, there are remnants of plaster muqarnas in three rows.

Earthen building materials have been in common use as cheap, available, and practical construction materials in hot and dry areas for a long time. Earthen buildings exist in Iran, especially in villages, because of the large and numerous areas that have the same climate. Given that Iran is highly earthquake prone and the importance of paying attention to the possible vulnerability of all the indigenous buildings, endeavours for identifying the possible weak points of the earthen village buildings in an earthquake situation become doubly important. Especially to save human life. On the other hand traditional building methods and life patterns related to village earthen buildings are an important part of the Iranian architectural history in using local building materials that need conservation. One of the collections of earthen buildings that has been damaged and has suffered various degradation during the Tabas earthquake of 1979 is the village of Esfahak located 38 kilometres south-east of the Tabas county, which has also been inscribed in the National Heritage List of Iran. After the aforementioned earthquake and the damage and destruction of the earthen houses in this region, the survivors left these buildings and started constructing buildings using new materials and building styles that clashed with their old architecture just a short distance away. But currently, with the focus on indigenous heritage and the development of the indigenous tourism sector, the residents in this area are asking for the repair and restoration of these buildings. In this respect and before any action is taken on strengthening the above-mentioned buildings, it is essential to study the earthquake damage in these buildings. A remarkable point related to the earthen buildings, is the different rates of damage in these buildings during the earthquake. Some of the buildings have suffered serious damage while other others have only minor damage or are completely unharmed. The existence of possible difference in the architectural template and the implementation method for these buildings is a possible factor in the variance in the rate of damage in the buildings and better performance of some of these structures during the earthquake. Examining the validity of this matter and a study on the existence of other factors influencing the difference in performance of some of these earthen structures have been done in this research. In this research, a field study of the different rates of damage in the earthen structures has been used as a basis to perform diagnostic studies in attaining the reasons for the structural failures of the earthen buildings in this village. Apart from endeavouring to reach a correct understanding of the seismic behaviour and the damage in these structures form the earthquake, such research is a precursor for any type of seismic improvement of these structures. This research is descriptive-analytical and the required information has been gathered using academic and field studies. The results of this research show that the passing of the Qanat underneath some of the homes has resulted in the increase in the damages. Also the different building patterns used for the structures (troglodytic, strata, moulded mud brick), has a direct impact on the seismic performance of these structures.
The low implementation quality, and not using the appropriate structural strengthening methods to increase the seismic resistance of these buildings by the builders is another reason for the different rates of damage in these buildings.

The Bāgh-e Fīrūzi area spreads over 130 ha and includes 10 known Achaemenid sites: seven with stone architectural elements, one with baked bricks on the surface, and two corresponding to 3 m-high rounded tepes. Tol-e Ājori is located on the eastern fringe of Bāgh-e Fīrūzi, on a border defined by Bāgh-e Fīrūzi located 300 m to the SE and Tol-e Jangī B located 400 m to the NW. This area was studied and excavated over 8 years.  Comprehensive study of Tol-e Ājori, located 3 km west of the Persepolis Terrace, must be approached by taking into account former research on Pārsa. Like various scholars before us, we think that the Bāgh-e Fīrūzi area should be seen as a part of the city linked to the royal residence of Persepolis. Remains of Achaemenid occupation near the village of Fīrūzi have gradually been brought to light by archaeologists surveying the vicinity of the Terrace in the attempt to place it within the perspective of wider town planning. 
 The archaeological excavation results in this part of the city of Pārsa showed that in both historical and functionality sense, the discovered building in Tol-e Ājori in the area known as Bāgh-e Fīrūzi, can go back to the early phases or even before the construction of the Persepolis terrace. The Tol-e Ājori is one of the valuable archaeological finds that fills the gap in the formation of the city of Pārsa before Darius I. Paying attention to the glazed bricks and the figurative imagery of fantastical animals used in this building, the building in Tol-e Ājori goes back to before the construction of Āpādānā in Susa and Persepolis, and it resembles the Ishtar gate in Babylon at the beginning of the sixth century BC. In this regard, the comparison of the construction method; architectural trend; and analytical archaeological information with regards to the construction methods; and identification of the the materials used for glazed bricks from the three areas of Tol-e Ājori, Susa and Babylon will have a critical role in understanding the history and the cultural connections of this era in South-Western Iran. The Tol-e Ājori building and the surrounding structures are located 3.5 kilometres from Persepolis, and they highlight the importance of the cityscape in this part as the oldest urban area within Pārsa. This research is conducted for the first time after new archaeological discoveries by using multidisciplinary research studies of the joint Iranian-Italian archaeological teams in the Pārsa city of Persepolis , and within the framework of the cooperation agreement between University of Bologna, Archaeology Research Centre, cooperation of Cultural Heritage Organisation, Shiraz University, and Persepolis World Heritage site.