vantage points as an argument for how there is much that is revealed about the affects of war/the nature of war.  Or, one can consider what is revealed with the 3 points of view about the psychology of a person in a life-or-death situation.

Aren't we splitting hairs here? Peyton might well be hallucination, but the author uses this as a flashback to earlier occurrences in Peyton's life. Hence it is a flashback. What I find interesting about the structure is that the story travels so far in such a short span of time for Peyton. 

The story is structured in three parts, and each part is labeled, I, II, and III. Part I begins at Owl Creek Bridge as the company of soldiers is preparing to hang Peyton Farquhar. It ends with the sergeant stepping off the board on which Peyton stands, the rope around his neck.

Part II is exposition, the flashback that explains how Peyton got himself into so much trouble; he had been set up by a Federal scout (a spy) and had attempted to burn the bridge to stop the advancing Union army.

Part III takes the reader back to the bridge as Peyton falls through the timbers, the rope around his neck. At this point, Bierce performs a literary sleight-of-hand, making it seem that Peyton has escaped and managed to return home. At the end of Part III, however, Peyton hits the end of the rope, his neck breaks, and he dies, his body hanging below the bridge. The reader realizes that Peyton's "escape" had happened only in his mind in the few seconds between his fall and his death.

In studying the structure of the story, pay special attention to the last sentence in each part. Each one is significant in advancing the plot.

You clearly need to be aware of how the author uses flashback in the story to indicate what intense and powerful memories can be experienced by someone in the few seconds before they die. I don't want to give you a spoiler, but will assume that you have read the story and therefore realise that Peyton Farquhar doesn't escape - we are the privileged viewers of his imagined escape and outwitting of the troops, when in fact these imaginings are condensed into the time that it takes for a man to be pushed off a bridge with a noose around his neck.

One primary literary device or structure used in "The Occurrence at Owl Creek Bridge" is flashback.  As he was preparing to be hanged, the man convicted of treason went back in time and we discover how he got where he is now.  Once the hanging begins, the rope breaks.  I assume you've read it, and you therefore understand that Peyton Farquhar never really left the site of his hanging but did "escape" in his mind.  This is clearly a deception on the part of Ambrose Bierce; he manipulates time and space in order to deceive readers into believing Farquhar is actually free.  Without these two elements, the story is one of a simple hanging for treason committed during the Civil War.

Creating the standard plot chart for this story isn't quite as straightforward as it is for other short stories. The reason for this is because the story isn't told chronologically. A fairly substantial flashback occurs in part 2, so a reader has to decide whether or not that is part of the exposition, rising action, or both.

I don't feel comfortable saying that the exposition is entirely in section 2. Readers are introduced in section 1 to a man being hanged. The story begins en medias res; however, that still counts as an exposition. This starting format is a standard "how did we get here" approach, and we aren't given many details of who the main character is before being hit with rising actions involving the soldiers moving into their final positions before dropping the man from the bridge.

I would claim that part 2 is a big rising action in and of itself as well. It doesn't fit chronologically because it gives exposition details about who Farquhar is and why he was on the bridge; however, the entire section adds massive tension to the story because readers know the man is falling, but we are ripped away from that moment. Bierce is holding our tension for a longer period of time by not letting us know what is happening to the man on the bridge. Section 2 ends with another small piece of information that further increases tension because we are told that Farquhar was clandestinely setup.

An hour later, after nightfall, he repassed the plantation, going northward in the direction from which he had come. He was a Federal scout.

Section 3 contains rising action after rising action. Farquhar's escape is both harrowing and miraculous, and things seem to get worse and worse. The climax occurs when Farquhar evades the final shot of grapeshot and plunges into the forest. Readers relax at this point, and Farquhar does as well. He's traveling home. This sequence is the falling action, and the conclusion is his death by hanging on the bridge. Readers realize that Farquhar imagined the entire escape.

Peyton Fahrquhar was dead; his body, with a broken neck, swung gently from side to side beneath the timbers of the Owl Creek bridge.

The external structure of this story, with its division into three parts, is complicated. Because the events do no unfold in chronological order, the exposition-through-denouement pattern is also not chronological. To trace the dramatic structure, it becomes necessary to arrange events in chronological order. Here's the chronology of events in actual order: 

Peyton is described as a loyal Southerner who longs to participate in the war. He speaks to a soldier whom he assumes is a Confederate. The soldier is instead a Union scout who gives Peyton the idea of burning Owl Creek Bridge. Peyton attempts to burn the bridge and is captured. As the Union soldiers prepare to hang Peyton, his fear affects his mind as he surveys his surroundings. He is hanged. As his body falls into Owl Creek, his mind acts to protect him at the moment of his death as he fantasizes about escaping and returning home to his wife's arms. His falling body hits the end of the rope, breaking his neck. His dead body then swings back and forth from the end of the rope below the bridge.

In this chronology, the establishment of Peyton's character would serve as exposition. His discussion with the Union scout would comprise rising action which would continue until the moment Peyton reaches out for his wife's arms. The sharp pain he feels in his neck represents the turning point or dramatic climax of the story:

As he is about to clasp her he feels a stunning blow upon the back of the neck . . . .

The falling action makes the reality of Peyton's situation clear:

. . . a blinding white light blazes all about him with a sound like the shock of a cannon--then all is darkness and silence!

Finally, the last paragraph of the story serves as its denouement:

Peyton Farquhar was dead; his body, with a broken neck, swung gently from side to side beneath the timbers of the Owl Creek bridge.

By structuring his story in such an unusual way, Bierce creates a very shocking--and ironic--conclusion.

The story structure is dramatic because it goes between three different realities--the present, the past and what is happening only in the main character's mind. The reader is confused which is real and which part is only in his mind.

At the beginning, before the reader sees the man actually being hanged, the past is introduced to the reader, as a sort of backstory. The backstory is set up in such a way as to elicit sympathy from the reader because the man was only a civilian who really wanted to help in the army but couldn't.

Next in the plot, when the the structure returns to the present, it appears as though the man escaped, which adds drama to the story because at that point the reader doesn't know it was only in his head. (Not until the end does it becomes apparent that he was only dreaming.)

At the beginning, a man, (Farquhar) is on a railroad bridge waiting to be hanged. He cannot move because his hands are tied and a noose is around his neck.

There are two different scenes on either side of the stream--one side is a forest and the other is a forte. This contrast is the writer's foreshadowing. It shows a contrast between freedom and war. The forest represents freedom and the fort represents war or death.

Soldiers form a line between the bridge and fort, all armed. When the captain gives a signal, a man will step off a board which will tilt down, and Farquhar will fall down to the stream between the boards and will hang.

The man Farquhar tries to think about his family but the sounds nearby become so loud he cannot think. He imagines how he could escape.

The story structure changes at that point to show the reader his past, that lead to him being hanged.

He was a Southern plantation owner who could not serve in the army. He wanted to however so when he met a Confederate soldier one night who stopped at his plantation he asked some questions about the war. The soldier told him that they were working on the railroad near Owl Creek Bridge. The Yankee commander said that anybody, even a civilian who tried to stop the building of the bridge would be killed. Later the soldier went by the plantation again,working as a scout for the Union Army.

The story structure comes back to the present as Farquhar falls between the railroad ties into the stream. He is unconscious. He regains his consciousness and splashes around in the stream. He realizes that the rope broke. He first goes to the bottom then comes up again and gets the ropes off his wrists. He takes in some fresh air and everything in sight crystallizes. He can see everything in sharp contrast--the fort, the soldiers who are pointing at him. A bullet almost hitting him.

He takes a dive missing a lot of bullets aimed at him. He comes up out of the water and he is downstream. A canon is fired but the forces of the water just push his out of harms way.He runs through the forest all day long and discovers a road that leads to his plantation.

He is walking, miraculously, even though his tongue is all swelled up and he is totally exhausted. His wife meets him on the porch.

He reaches out to embrace her, and feels an intense blow to the back of his neck. Farquhar suddenly sees bright white light and then there is only blackness. He is dead. His body is swinging from Owl Creek bridge.