All of the plaintiffs' claims are dismissed.

The costs of lawsuit shall be borne by the plaintiffs.

Basic Facts

A. Construction contract between the plaintiffs and the defendant 1) The plaintiffs are joint contractors (supply ratio: 70% for the plaintiff A corporation, 10% for the plaintiff D corporation (former E corporation), 10% for the plaintiff B corporation, 310% for the plaintiff corporation, 310% for the plaintiff corporation, and hereinafter "joint contractors of this case").

On December 13, 2011, the term “instant construction project” consisting of the Defendant and the Defendant for the extension of the national expressway fund (section 6; hereinafter “instant construction”).

As to a long-term continuing contract, the contract was concluded by adding the total construction period to KRW 1,500, and the total construction cost to KRW 61,131,31,313,371, and stipulating the construction period of the first contract among the instant construction works as KRW 10,000 from December 13, 201 to December 29, 201 (hereinafter referred to as the “instant construction contract”) in the form of a long-term continuing contract (hereinafter referred to as the “the instant contract”).

(2) The general conditions and special conditions of the instant construction contract are as follows.

(4) The ratio of winning expenses, such as indirect labor expenses, industrial accident insurance premium and occupational health and safety management expenses, to the increase or decrease of the contract amount under paragraphs (1) and (2), and general management expenses and profits, shall be based on the ratio of winning ratio, such as indirect labor expenses, industrial accident insurance premium rate and occupational health and safety management expenses, and the ratio of general management expenses and profits on the calculation sheet, but shall not exceed the ratio prescribed by relevant Acts and subordinate statutes, the Minister of Strategy and Finance, etc. at the time of design change.

(7) When the Corporation adjusts a contract price under paragraphs (1) through (6), it shall do so within 30 days from the date it receives a request from the other party to the contract for the adjustment of the contract price.

In such cases, the period of adjustment may be extended after consultation with the other party to the contract, if it is inevitable, such as delay in allocating the budget, and when there is no budget to adjust the contract amount, the volume of construction, etc.