Investigation toward the adoption of building information modelling (BIM) in Algeria from architects' perspective

: The present paper attempts to identify and assess the individual perceptions of BIM benefits and implementation barriers in the construction industry in Algeria from architects’ perspective. An investigation was carried out through survey questionnaires distributed to Algerian architects with different profiles. A total of 100 questionnaires were used for the study. A subgroup analysis was conducted in order to investigate the differences in the individual perception of the different groups of architects segmented according to the respondent’s work type, organisation size, experience length, and CAD and BIM knowledge. The findings of the study revealed that the most important barriers to BIM implementation were people and policy factors. The subgroup analysis revealed that the architects working for design firms were more aware and had more readiness for adopting BIM, compared to those working for project owners and contractors. Moreover, there were differences in the BIM maturity level between the big size and small size organisations in Algeria. It was concluded that, in the actual BIM maturity level, the BIM implementation would not occur without the implication of local authorities and policymakers as they have a significant impact in promoting and accelerating BIM adoption in the country.


INTRODUCTION:
Nowadays, information and communication technology (ICT) are becoming inevitable due to the complexity and the big size of construction projects (Van Roy et al., 2020). Furthermore, the construction sector has experienced a quantitative evolution in the data shared between the building sector's actors. The BIM was developed as the solution to facilitate and increase collaboration between different actors in a construction project. Thus, a race towards the adoption of BIM has been noted all over the world.
Talking today about the implementation of BIM in the construction industry in Algeria has become essential. In the near future, the construction industry will be most likely required to implement BIM. As it is now unthinkable for a design firm to present construction documents where plans are represented with the traditional method of drawing lines, it will be unimaginable shortly to design a project with the traditional process that we know today without the use of BIM.
In Algeria, the actors in the construction industry continue to work separately with traditional design and construction methods, whether DESIGN-BID-BUILD (DBB) or DESIGN-BUILD (DB). However, several problems are associated with these traditional methods of the construction industry as the lack of efficiency, a high number of errors due to lack of coordination, lack of interoperability and incompatibility, as well as the poor investment in IT technologies (Arayici, 2015). In fact, it is only recently that interest in BIM has arisen in Algeria.
Since 2015 several events and workshops have been organised in different cities of the country to debate the issue of BIM implementation and the readiness level of the Algerian AEC industry.
Furthermore, several private training institutions have recently started to promote the implementation of BIM in Algeria through the support of certain organisations by establishing a BIM approach. However, except few initiatives to promote BIM, it seems that most actors in the construction industry are not yet interested in undertaking BIM as a design and construction process in Algeria. This research particularly tries to answer the following questions: Do the profiles of architects impact the implementation of BIM in Algeria? Are there differences in the perception of BIM practice between architects, or are there other more impacting factors?
Thus, this research was conducted to identify and assess the individual perceptions of BIM benefits and implementation barriers from the architect's perspective. Furthermore, this paper extends Bouguerra et al. (2020aBouguerra et al. ( , 2020b research on the BIM implementation in Algeria by focusing only on the architect's viewpoint and by investigating the differences in the perception of BIM practice according to different multi-influence factors, namely, work type (design firm, project owner, contractor), organisation size, experience length, and CAD and BIM knowledge.
The findings of the study also contribute to improving and developing a consistent implementation framework of BIM in Algeria and other countries with similar contexts and 3 construction environments. Furthermore, this study extends the existing knowledge on the perception of BIM and leads to further discussion of how architects from less mature BIM countries perceive BIM practice compared to their counterparts from more BIM mature countries.

LITERATURE REVIEW:
BIM is defined by National BIM Standard-United States (2015) as "a digital representation of physical and functional characteristics of a facility. As such, it serves as a shared knowledge resource for information about a facility, forming a reliable basis for decisions during its life cycle from inception onward". Initiated in the 1970s by Charles M. Eastman (Wong, Wong, & Nadeem, 2011), BIM is considered the next paradigm shift in the construction industry (Shelden, 2009). Due to the capability of BIM to improve productivity while reducing cost and construction delay earned, it is considered "the most promising recent development in the architecture, engineering, and construction (AEC) industry" (Azhar, 2011). Countries that had implemented BIM observed a real improvement in terms of project planning, design, construction, and maintenance phases (2011). However, it seems like the BIM implementation varies from each country depending on different factors (Gu and London, 2010). The identification of the BIM implementation barriers has been considered preliminary for enhancing BIM implementation (Kassem et al., 2012). In response to this, several studies investigated BIM adoption and implementation in both developed and developing countries.
According to Sahil (2016), the BIM adoption issues are the same in both developed and developing countries. However, this can be true only if the comparison has been made at the same BIM maturity level. In fact, differences can be identified in BIM implementation barriers according to the BIM maturity level of each country. Succar (2010) described the BIM maturity level as "…the quality, repeatability, and degree of excellence within a BIM Capability'.
The following sections elaborate on major barriers to the implementation of BIM identified in previous studies. This will allow identifying for the survey the barriers likely to the implementation of BIM in Algeria. Table 1 shows the map of BIM implementation barriers worldwide. For the developed countries, it seems more appropriate for this research to select studies carried out at a low level of maturity that reflect the real barriers for first initiatives aiming at BIM implementation. For Eadie et al. (2014), there were differences between barriers to BIM implementation from the perception of those already using BIM and those that have not implemented BIM. According to Kalfa (2018), in 2003 the United States of America set up a national 3D-4D BIM program to support the implementation of BIM for the realisation of public projects while Europe, Norway, Denmark, and Finland have supported BIM implementation since 2007 (Granholm, 2011;MacAuley et al., 2017). In 2011, the United Kingdom started a program to use BIM level 2 in the construction industry (MacAuley et al., 2017). However, in Asia, Japan, Korea and Hong Kong, guides have been established to enhance BIM adoption in the construction industry since 2009 (Cheng and Lu, 2015).

BIM implementation worldwide:
In the UK, Sebastian (2010), cited by , tackled the insufficient evaluation of BIM value from the company level. However, for Eadie et al. (2013), it was the training and software cost, and the lack of idea about the benefits constituted the most important barriers to BIM implementation. The National Building Specifications (NBS), the UK institution that monitors BIM implementation, had established in 2013 a report about BIM implementation in the UK, Canada, Finland and New Zealand, and concluded that the most important barriers to BIM implementation were the lack of expertise, lack of standardised tools, lack of collaboration protocol, and the cost. However, the latest NBS Reports (2018, 2019) focusing only on the UK has identified that the main BIM implementation barriers were no client demand, lack of training, cost, lack of in-house expertise, and no time to get up to speed.
On the other side, several researches have been conducted on the implementation of BIM in developing countries. For example, in India, Vinoth Kumar and Mukherjee (2009) found that the main BIM implementation barrier is the lack of technical experts. Moreover, Nanajkar (2014) added that the lack of clients' demand, lack of qualified staff, and the high cost of training. In 2018, Arunkumar et al. identified 19 main barriers to implementing BIM. Among those barriers, the most significant factors were related to cultural resistance, the lack of supply chain buy-in, the lack of ideas about the benefits, the cost of software and hardware, and the lack of professionals, (Arunkumar et al.,2018).
In Malaysia, Zahrizan et al. (2013) conducted research on the BIM implementation barriers and concluded that the top barriers were the lack of knowledge and awareness, lack of policymakers' support, and lack of standards. In 2019, Jamal et al. conducted a survey about the BIM barriers implementation and found that the top three BIM implementation barriers were related to the lack of BIM experts, the difficulty of learning, and the high cost of software and hardware.
In Indonesia, Van Roy et al. (2020) conducted a survey to investigate BIM practices and implementation barriers in the AEC industry. They found that the most critical barriers were the lack of BIM training, the lack of BIM capability, the lack of requirements from the client, the software and hardware high cost, and ICT issues.
In Nigeria, studies were conducted by Amuda-Yusuf et al. (2017) and Ogwueleka et al. (2017) on the BIM implementation barriers in Nigeria. The researchers found that the major barriers to the BIM implementation were clients' awareness, funding issues, lack of incentive and supply, lack of transparency and legal uncertainty.
In Egypt, Marzouk et al. (2021) conducted research by investigating the BIM implementation and proposing strategic solutions for the Egyptian AEC industry. The researchers found that the challenges to the BIM implementation in Egypt were within the lack of BIM awareness, cultural resistance, the lack of standards and regulations and the lack of requirements from the client. In addition, the research highlighted the role of government and educational institutions by providing incentives and spreading awareness to facilitate BIM adoption in Egypt. Saka et al. (2019) investigated the intellectual evolution of BIM in the African AEC industry.
The study is based on a scientometric review and meta-synthesis of BIM development in African countries. The researchers selected for the meta-synthesis five countries that cover four regions of the African continent: Kenya, Ghana, Nigeria, Libya, and South Africa. The findings revealed that the major barriers facing the implementation of BIM in these countries were people and process barriers, followed by economic and technology barriers. The critical barriers could be summarised as lack of requirements from the client, legal uncertainty, lack of experts, lack of management support, resistance to change, lack of government support, lack of awareness, lack of training, implementation high cost, interoperability, lack of idea about BIM benefits, lack of BIM standards, and lack of collaboration.

BIM implementation in Algeria
In Algeria, it is only recently that interest in BIM has arisen. In 2015, the first BIM event was organised to discuss the need to promote the implementation of BIM in Algeria. Since then, This belated interest in BIM implementation in the AEC industry in Algeria is due to the context and the culture of this country. One of the factors marking this Algerian context concerns the delay recorded in the digitalisation of the construction industry, as well as the timid adoption of ICT technologies. It is only recently that the Algerian government has made the digitization of the entire Algerian administration a hobby horse of its political strategy. This technological issue forced the actors of the construction industry to work with traditional design and construction methods, except for major projects that were awarded to international firms.
Another factor concerns the strong impact of the local authorities and policymakers on the construction industry. As the majority of developing countries, the Algerian government controls the construction market through the budget allocated for the construction of public utility equipment, the various infrastructures and housing. As mentioned previously, the digitization of the Algerian administration is not yet operational, which currently prevents the government from requiring the implementation of BIM in its public projects.
Scholarly, during the 2018 ministerial reform of the architectural curriculum, BIM has been introduced as a module " modelling and simulation BIM" for the third level of architectural training in the LMD (Licence-Master-Doctorat) system. This initiative is a very important step in the implementation of BIM in Algeria. First of all, it helps to overcome the barrier of lack of BIM training for architects. Secondly, it trains and initiates the next generation of architects to adopt BIM as a design and build process.
Research was carried out by Bouguerra et al. (2020a) to investigate the best practices and the challenges of BIM implementation in the AEC industry in Algeria. The researchers conducted a questionnaire survey from practitioners' perspectives (architects, engineers, and contractors) in Algeria. The challenges were classified into three groups: technology, process, and policy.
The researchers found that the most critical challenges were within policy and process factors followed by BIM technology factors. On one hand, the most critical challenges could be summarised as a lack of standards on how to collaborate, lack of contractual agreement, lack of the client's requirements and the BIM software high cost. On the other hand, regarding the best practices, the findings were consistent with challenges where more effort should be taken regarding policy and process factors compared to technology. In another research based on the same survey, Bouguerra et al. (2020b) investigated the BIM awareness, capabilities, and maturity of the Algerian construction industry. The study proposed a mixed approach to implementing BIM with both the government and the industry. The finding suggested a preliminary framework for the implementation of BIM based on previous theories and the questionnaire survey's findings, "starting with the technical aspect such as training and awareness, then policy aspects such as BIM drivers support and motivation, followed by process aspects such as change management and finally, changing the contractual environment and elaborating a national BIM policy and mandating BIM usage" (Bouguerra et al., 2020b).
The present paper tries to investigate if the profiles of actors in the construction industry impact the implementation of BIM in Algeria. Thus, this research will focus on the viewpoint of architects by studying the individual perceptions of BIM benefits and implementation barriers from the architect's perspective. Different multi-influence factors selected in the current study, namely work type (design firm, project owner, contractor), organisation size, experience length, and CAD and BIM knowledge, extends the current knowledge on BIM individual perceptions and contributes to improving the implementation framework of BIM in Algeria and other countries with similar construction environment and context.

RESEARCH METHODOLOGY
This research adopted a questionnaire survey followed by statistical analysis in investigating the individual perceptions (architects) of BIM benefits and implementation barriers in Algeria.

Data Collection
The collection of data on the BIM implementation barriers in Algeria was performed through an empirical survey. The data collection process followed the procedures described by Cao et al. (2016) and Jin, Hancock, Tang, Wanatowski and Yang (2017), with various ways to reach potential survey participants, including events, seminars, and online surveys (online questionnaire using Google Form). The data were collected twice, first in January 2020 and the second in November 2020 to extend the sample size. The questionnaire was delivered to potential participants with different architect profiles (view Table 2).
A non-probability sampling technique was used to select a representative population for this research. The sample size was calculated based on the following formula (1) and (2) for the sample size n (Daniel & Cross, 2018;Naing et al., 2006): n (1) = N*X / (X + N -1), (1) where, X (2) = Zα/2 2 *p*(1-p) / d 2 , (2) Zα/2 is the critical value of the Normal distribution at α/2. With α 0.1 and a 90% of confidence level, the critical value is 1.645. d is the margin of error MOE (8% used for this study), p is the sample proportion (0.25 is used for the sample size needed), and N is the population size.
The population size of this research was estimated at 10 000. This estimation included: around 10 000 certified architects in Algeria (According to the National Council of the Order of Architects -CNOA). Then, from formula (1) and (2), n = 78.5 In this study, a total of 100 respondents completed the survey. This suggested that the sample size was representative and enough for the current research.
The questionnaire (in French) had three parts. The first part included the purpose of the study.
It covered questions that focused on the background information of participants including their work type (e.g., design firm, project owner, contractor, etc.), their CAD and BIM knowledge, their organisation size, and working experience on CAD and BIM projects. The second part of the questionnaire was adapted from a similar study conducted by Liu et al., (2019) The barriers in our questionnaire were identified after a comprehensive review of the literature presented in section 2. From the results of the previous studies on BIM implementation presented above, several factors appeared several times in both developed and developing countries such as software and hardware cost, no client demand, resistance to change, lack of government support, and lack of BIM standard (view table 1).
The respondents were asked to evaluate every single factor using a five-point Likert scale, where 1 meant that the factor was not important while 5 meant that the factor was very important. The 5-point scale is the common (universal) method of collecting data used in most studies, the format aligns with a vast library of comparative external benchmark data. To identify potential practical problems as well as problems with the survey design, a pilot study with 15 questionnaires preceded the main survey. The results of the pilot survey helped to improve the questionnaire.

Reliability analysis (Cronbach's alpha)
Reliability analysis was adopted to examine the internal consistency of the factors through the use of Cronbach's alpha (Kim et al., 2016;Chileshe et al., 2016).

Ranking analysis
The ranking of BIM benefits and implementation barriers in Algeria was performed as indicated in Chileshe et al. (2015) by examining the descriptive statistics (mean score values, standard deviation). The mean score values represented the relative importance of each factor while the standard deviation represented the degree of compromise between participants (Kim et al., 2016). Where two or more factors had the same mean values, the ranking was performed by selecting the factor with the lowest standard deviation (Doloi et al., 2012).

Subgroup analysis (ANOVA)
The survey sample was segmented into subgroups according to the respondent's work type, organisation size, respondent experience length, and CAD and BIM knowledge. ANOVA was adopted to analyse the differences in the perception of benefits and critical barriers to the BIM implementation in Algeria, as indicated by Liu et al. (2019). An F-value and a p-value were calculated for each factor by taking the level of significance of 5%. A p-value lower than 0.05 suggests that differences were found between the groups of respondents. To identify the source of differences, univariate ANOVA tests were conducted as indicated in Yuksel et al. (2000).

Profile of Respondents
A summary of the background information of the respondents is presented in Table 2. The respondents consist of architects with 60% working in a design firm, 25% working for a project owner, and 15% working for a contractor. The age of respondents varies between 20 and 60 years. More than 80% of respondents ranged from 20 to 39 years. The organisation size of respondents varies from 01 employer (10%) to more than 10 employers (24%). 41% of the respondents had their organisation size with less than 5 employers, and 25% with 05 to 10 employers.
According to Table 2, the experience length of respondents (as architects) varies from less than 01 year to more than 30 years. 44% of respondents have an experience length from 01 to 05 years, 33% have an experience length from 06 to 10 years, 11% have an experience length from 11 to 20 years, 8% have an experience length less than 01 year, 3 % have an experience length from 21 to 30 years, and only 1% of respondents have an experience length more than 30 years.
Regarding CAD and BIM software mastery use by the respondents, 37% use BIM software like Revit and ArchiCAD, 34% are experts in CAD software (2D / 3D modelling), 23% only use 2D modelling with CAD software, 5% are BIM expert (mastery of a collaborative platform that has already provided BIM coordination in a construction project), and only 1% have no mastery of CAD (computer assisted drawing) software such as AutoCAD.

Reliability analysis:
The five-point scale has been found reliable with Cronbach's alpha of 0.93 for BIM benefits and 0.88 for BIM implementation barriers (higher than 0.7), which reflects the high internal consistency of participants' perceptions.

BIM benefits:
The respondents were asked to rank items related to BIM benefits using a five-point Likert scale. The ranking of the individual perception toward BIM benefits is based on their means value and standard deviations. Table 3 presents the ranking of these factors.
According to Table 3, the respondents ranked "Strengthen collaboration between the different actors of the project (client, project manager, construction company)" as the top BIM benefits with a mean value of 4.13. The other higher-ranked BIM benefits were "offering new services" with a mean value of 4.04, "better project quality" with the mean value of 4.03, and "Reduction of omissions and errors" with a mean value of 4.00. Subgroup analysis based on the work type, organisation size, experience length, and CAD and BIM knowledge of respondents is summarised in Table 04.
The table 4 shows that there were consistent perceptions of BIM benefits for all the subgroups of respondents. Therefore, the perception of the "BIM benefits" seems to be similar for all groups of respondents in our sample.

Barriers to the BIM implementation
The respondents were asked to rank items related to BIM implementation barriers using a fivepoint Likert scale. The ranking of the individual perception toward BIM implementation barriers is based on their means value and standard deviations. Table 5 presents the ranking of these factors.
As inferred from Table 5 the three most important barriers to BIM implementation in Algeria were related to the people factor. The survey participants agreed that the first barrier was "the lack of experienced and qualified professionals in BIM" with the mean value of 4.29 and standard deviation of 1.01 while the second was "the non-involvement of local authorities in the application of BIM" with the same mean value of 4.29 but a higher standard deviation of 1.09, and the third barrier was "the clients do not require the application of BIM in their projects" with the mean value at 4.23.
The policy area was ranked as the second most important factor with the fourth, fifth, and sixth most important barriers. The survey participants agreed that there was a "lack of best BIM practices within the construction industry" with a mean value of 4.10, a "lack of support and absence of incentives for promoting BIM by the policymakers" with a mean value of 3.93, and "No legal or contractual agreement on BIM" with mean value at 3.78.
Barriers ranked from seven to thirteen were mostly derived from process and technology factors. Regarding the process factors, survey participants agreed that there was reluctance to change working methods by project stakeholders with a mean value of 3.52. Respondents also agreed that the most important technology barrier was the high cost of BIM hardware and software with a mean value of 3.46. Lack of BIM data library and standards 3.14 1.14 10 S3 Reluctance to change working method by project stakeholders 3.52 1.14 8 Subgroup analysis based on the work type, organisation size, experience length, and CAD and BIM knowledge of respondents is summarised in Table 06. According to Table 6, there were significant differences in the BIM implementation barriers perception of the different groups segmented according to work type variables in light of T2 related to the BIM lack of functionality or flexibility to produce a 3D model (P 0.029), and S1 "BIM does not reduce the time spent on planning" (P 0.019). Table 6 indicates the differences between subgroups according to work type by adopting univariate tests ANOVA. From Table   7, it is seen that the difference came from the contractors. The architects working as or for contractors held significantly more confirmatory views on T2 (BIM lacks functionality or flexibility to produce a 3D model) with an average score of 1.93, compared to the architects working for design firms (2.80) and project owners (2.76).
Similarly, respondents working for contractors also held more confirmatory views on S1 (BIM does not reduce the time spent on planning) with a scoring average of 1.53, compared to the architects working for design firms (2.32), and project owners (2.52). The subgroup analysis based on the organisation size of respondents (table 6) revealed that there were differences in the BIM implementation barriers perception in light of P1 related to the culture change and mindset issues (P 0.029), T1 "High cost of BIM hardware and software" (P 0.038), and T2 "BIM lacks functionality or flexibility to produce a 3D model" (P 0.010). Table   8 shows that respondents from organisations with more than ten employers held less confirmatory views on P1 compared to the other organisations with fewer employers.
Respondents from organisations with more than ten employers had the lowest average Likertscale score of 2.92, indicating a neutral attitude. Moreover, table 8 shows that respondents from organisations with 5 to 10 employers and more than ten employers were more likely to consider T1 as an important BIM implementation barrier, with average scores of 4.04 and 3,90, respectively. Furthermore, respondents from organisations with 5 to 10 employers (3.24) and more than ten employers (3.29) held less confirmatory views on T2 compared to the others organisations with fewer employers. The average scores on T2 for organisations with one employer and less than 05 employers were 3.50 and 3.15, respectively. The subgroup analysis based on the experience length of respondents (table 6) revealed that there were differences in the BIM implementation barriers perception in light of T1 "Issues of interoperability and data exchange" (P 0.004). Table 10 shows that respondents with an experience length of less than five years were more likely to reject T1 as a critical barrier to BIM implementation in Algeria than respondents with more experience length. The average scores on T1 for respondents with experience lengths less than one year, 01 to 05 years, 06 to 10 years, 11 to 20 years, 21 to 30 years, and more than 30 years were 2.27, 2.70, 3.17, 3.11, 3.67, 3.00, respectively. Furthermore, the subgroup analysis based on the respondent's CAD and BIM knowledge (table 6) revealed that there were significant differences in the BIM implementation barriers perception in light of T2 "BIM lacks functionality or flexibility to produce a 3D model" (P 0.004).
With an average score of 1.29 (Table 10), the respondents who were BIM experts were more likely to reject T2 as a BIM critical implementation barrier compared to those with no mastery of CAD (3.33), mastery of CAD software in 2D (3.15), proficiency in CAD software in 2D/3D (2.78), and who use BIM software like Revit and ARCHICAD (2.15).

DISCUSSION
Through the results of the ranking analysis related to BIM benefits, it has been found that strengthening collaboration between the different actors of the project, offering new services, and reduction of omissions and errors were considered the most important BIM benefits. These most important BIM benefits were generally consistent with the findings of Liu et al. (2019) and Jin et al. (2015), who conducted a survey of the same question to AEC practitioners in China. However, there were differences in the top-ranked BIM benefits ("offering new services" by Liu et al. (2019) and "reduction of omissions and errors" by Jin et al. (2015)).
Therefore The findings seem to be coherent with the study results of Bouguerra et al. (2020a) related to the challenges facing the AEC industry for the BIM implementation in Algeria. This later found that the policy factors were the most challenging ones. It should be noted that Bouguerra et al. (2020a) grouped the challenges into three main factors only, and the people factors were grouped with the policy ones. Other studies, conducted in developing countries such as Malaysia (Zahrizan et al., 2013), Nigeria (Abubakar et al.,2014;Amuda-Yusuf et al., 2017), Egypt (Marzouk et al., 2021), and Iran , the first barrier of BIM implementation was related to policy factor and the role of policymakers in supporting and encouraging to promote the BIM.
The policy area was ranked as the second most important factor. The respondents agreed that there was a lack of support and absence of incentives for promoting BIM by the policymakers and a lack of best BIM practices within the construction industry. As in other developing countries such as Malaysia and Iran, the Algerian state has a crucial role and impact on the economy and the business environment. As long as the business plans of construction companies in Algeria is depending on the budget that the policymakers allocate to construction projects, these latter could be a force to encourage AEC companies to implement BIM in their projects. Another barrier indicated by the respondents was that there was no legal or contractual agreement on BIM. This is in agreement with the study results conducted in Malaysia by Zahrizan et al. (2013), Jamal et al. (2019), and in Iran by Hosseini et al. (2015) that indicated that the unavailability of documents and policies to regulate the adoption of BIM in construction activities, and the lack of understanding the legal and contractual relationship are critical barriers to the BIM implementation on a construction project in developing countries. As affirmed by Hosseini et al. (2015), construction companies, in this context, do not take the risk of adopting novel methods with uncertainties such as BIM and maintain their traditional methods .
Barriers ranked from eight to thirteen were mostly derived from process and technology factors.
This result echoes the findings of Abubakar et al. (2014) in Nigeria and Hosseini et al. (2015) in Iran. Regarding the process factors, survey participants agreed that there was reluctance to change working methods by project stakeholders. Such as in Iran, the AEC industry in Algeria is dominated by a traditional project delivery method. Consequently, a radical change in the working method of construction companies is necessary. However, this routine change is faced with a great level of resistance by project stakeholders in Algeria, which is understandable as the internet speed and the ICT required for BIM adoption is still a real issue with the delay of the Algerian state in implementing ICT solutions. Respondents also agreed that the most important technology barrier was the high cost of BIM hardware and software. As the adoption of BIM requires specific hardware and software, it affects the cost. It is important to point out that in other studies (Arunkumar, S et al. (2018) in India, Van Roy et al. (2020) in Indonesia, and NBS Reports (2019) in the UK, this barrier was ranked as the main factor. It seems that it has a relationship with the maturity of BIM in these countries (more mature BIM countries).
From this discussion, we can note that globally, the BIM maturity level of Algerian architects is approaching the one of developing countries (less mature BIM countries) studied in different periods (Malaysia in 2015, Nigeria in 2014, and Iran in 2015.
The subgroup analyses were performed according to the architect's work type, organisation size, experience length, and CAD and BIM knowledge. No differences were found in architects' perceptions of BIM benefits. However, several subgroup differences were found in architects' perceptions of BIM implementation barriers.
The subgroup analysis according to the architect's work type revealed differences in the perceptions of two barriers, one related to the BIM technology barriers while the second is related to the BIM process barriers. It appeared that the architects working for a design firm were more likely to reject the barrier related to the BIM's lack of functionality or flexibility to produce a 3D model compared to the architects working for a project owner or contractor. This can suggest that the architects working in design firms are more familiar with BIM software than the others. Similarly, the architects working for design firms held more confirmatory views on rejecting the barrier related to the BIM does not reduce the time spent on planning as a critical barrier, compared to the architects working for project owners or contractors. This result seems to be coherent with the precedent findings and confirms that the design firms have more capabilities and readiness for adopting BIM compared to the project owners and contractors.
The subgroup analysis according to the architect's organisation size revealed differences in the perceptions of some BIM implementation barriers between small size and big size organisations. It has been found that big-size organisations (more than ten employers) were more likely to reject culture change and mindset issues as a critical BIM implementation barrier compared to small-size organisations. This suggests that big-size organisations have more capabilities and readiness for adapting to new technologies and new working methods compared to small-size organisations. Furthermore, the big size organisations were more likely to consider the high cost of BIM hardware and software as a critical BIM implementation barrier compared to the small size organisations. This can suggest that there are differences in the BIM maturity level between the big size and small size organisations in Algeria. As mentioned above, the technology barriers were considered the most critical barriers in countries with high BIM maturity levels. The same goes for the technology barrier related to the BIM lack of functionality or flexibility to produce a 3D model, which the big size organisations held less confirmatory views on rejecting this barrier as a critical one compared to the small size organisations.
Moreover, the subgroup analysis, according to the architect's experience length, revealed differences in the perceptions of the BIM implementation barrier related to the issues of interoperability and data exchange (incompatibility between software). It appeared that architects with experience length of more than 06 years held less confirmatory views on rejecting this barrier as a critical one compared to less experienced architects. This result seems to be coherent with the precedent findings, as long as the experienced architects seem to have a high BIM maturity level compared to the less experienced architects.
In addition, the subgroup analysis, according to the architect's CAD and BIM knowledge, revealed differences in the perceptions of the BIM implementation barrier related to the BIM's lack of functionality or flexibility to produce a 3D model. It was further indicated that architects who had already used BIM software and those experts on BIM were more likely to reject this barrier compared to the others. This agrees with the aforementioned findings and can be explained by the fact that respondents who were more familiar with BIM software have enough knowledge of the BIM functionalities in 3D modelling than the other groups of respondents.

CONCLUSION
The study investigates the benefits and barriers of BIM implementation in Algeria from the architect's perspective. Several factors were identified as major benefits and barriers to BIM implementation by a group of survey constituted only of architects. Moreover, a subgroup analysis was undertaken by dividing the whole survey sample into several groups according to the architect's work type, organisation size, experience length, and CAD and BIM knowledge.
This paper extends Bouguerra et al. (2020aBouguerra et al. ( , 2020b) research on BIM implementation in Algeria by conducting an empirical study on barriers to BIM implementation in Algeria from the architect's perception and by studying different multi-influence factors, namely work type (design firm, project owner, contractor), organisation size, experience length, and CAD and BIM knowledge.
In this paper, thirteen barriers have been identified. These barriers were classified by factors cores components, which were People, Policy, Technology and Process. According to the ranking analysis, the most important barriers to BIM implementation were people and policy factors. The top five barriers were: (1) the lack of experienced and qualified professionals in BIM, (2) the non-involvement of local authorities in the application of BIM, (3) clients do not require the application of BIM in their projects, (4) the lack of support and absence of incentives for promoting BIM by the policymakers, (5) the lack of best BIM practices within the construction industry.
In addition, this study revealed the individual perception of BIM benefits from the architect's perspective. The main BIM benefits were strengthening collaboration between the different actors of the project, offering new services, better project quality, and reduction of omissions and errors.
The subgroup analysis according to the groups of architects mentioned above revealed differences in the perceptions of some barriers. These findings answer the first part of the study questions and suggest that the profiles of architects impact the implementation of BIM in Algeria. The findings of the analysis revealed that the architects working for design firms were more aware and had more readiness for adopting BIM compared to those working for project owners and contractors. Moreover, there were differences in the BIM maturity level between the big size and small size organisations in Algeria. It was found that the big size organisations have more capabilities for adapting to new technologies and new working methods compared to small size organisations.
The findings of the study brought to light that the Algerian AEC industry is lagging compared to other developing countries (more BIM mature countries) in terms of BIM implementation on construction projects. The ranking of barriers confirms this shift with people and policy factors as the most important barriers while technology and process factors are considered secondary barriers, which reflect the BIM readiness and maturity level of Algeria compared to other developing countries. These findings answer the second part of the study questions and suggest that, in addition to the impact of the architects' profiles on the BIM implementation, there are other more impacting factors. The impact and the great role of the local authorities and policymakers in promoting and accelerating BIM adoption in the country is very important in the actual maturity level. Therefore, first, Algerian authorities should impose the implementation of BIM for large-size public projects gradually through regulation. Secondly, the government should consider giving incentives to accelerate BIM training courses in private and public schools, which would enhance large construction companies to start including BIM learning as internal training for their employers and, consequently, implementing BIM in their projects.
Although this research investigated the perception of BIM benefits and critical implementation barriers from the architect's perspective, as part of future studies, it will be interesting to extend the sample size for studying the perception of both the construction industry and the educational institutions in the country.

Conflicts of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.